We thank Dr. Chao-Sheng Cheng at National Tsing Hua University, Taiwan, for performing the circular dichroism measurement. We also thank Drs. Evanthia Galanis and Ianko D. Iankov at Mayo Clinic, USA, for providing the anti-HP-NAP monoclonal antibody. We appreciate Drs. Han-Wen Chang and Chung-Chu Chen at Mackay Memorial Hospital, Hsinchu, Taiwan, for providing advice for IRB application, Mr. Te-Lung Tsai at the Mackay Memorial Hospital, Hsinchu, Taiwan, for supervising the analysis of isolated neutrophils, and Ms. Ju-Chen Weng at National Tsing Hua University, Taiwan, for her technical assistance. This work was supported by grants from the Ministry of Science and Technology of Taiwan (MOST 104-2311-B-007-003, NSC101-2311-B-007-007 and NSC98-2311-B-007-006-MY3), the Joint Research Program of National Tsing Hua University and Mackay Memorial Hospital (100N7727E1, 101N2727E1, 103N2773E1), and the research program of National Tsing Hua University (104N2052E1).

Human blood was collected from healthy volunteers with prior written informed consent and approval from the Institutional Review Board of the National Tsing Hua University, Hsinchu, Taiwan.
1. Expression of Recombinant HP-NAP in E. coli
<ol>
	<li>Prepare the plasmid pET42a-NAP containing the DNA sequence of HP-NAP from H. pylori 26695 strain as previously described16. Prepare the plasmids containing the DNA sequence of HP-NAP with the desired point mutations as described (see Protoco...

<ol>
	<li>Brunette, G. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+3,+Infectious+diseases+related+to+travel.">Chapter 3, Infectious diseases related to travel.</a> CDC Health Information for International Travel 2016. , (2015).</li><li>Bauer, B., Meyer, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+human+gastric+pathogen+Helicobacter+pylori+its+association+with+gastric+cancer+and+ulcer+disease.">The human gastric pathogen Helicobacter pylori its association with gastric cancer and ulcer disease.</a> Ulcers. 2011, 340157 (2011).</li><li>Malfertheiner, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Management+of+Helicobacter+pylori+infection--the+Maastricht+IV/+Florence+Consensus+Report.+Gut.">Management of Helicobacter pylori infection--the Maastricht IV/ Florence Consensus Report. Gut.</a> Gut. 61 (5), 646-664 (2012).</li><li>Evans, D. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+Helicobacter+pylori+neutrophil-activating+protein.">Characterization of a Helicobacter pylori neutrophil-activating protein.</a> Infect. Immun. 63 (6), 2213-2220 (1995).</li><li>Fu, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Helicobacter+pylori+neutrophil-activating+protein:+from+molecular+pathogenesis+to+clinical+applications.">Helicobacter pylori neutrophil-activating protein: from molecular pathogenesis to clinical applications.</a> World J. Gastroenterol. 20 (18), 5294-5301 (2014).</li><li>de Bernard, M., D'Elios, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+immune+modulating+activity+of+the+Helicobacter+pylori+HP-NAP:+Friend+or+foe?.">The immune modulating activity of the Helicobacter pylori HP-NAP: Friend or foe?.</a> Toxicon. 56 (7), 1186-1192 (2010).</li><li>Malfertheiner, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Safety+and+immunogenicity+of+an+intramuscular+Helicobacter+pylori+in+noninfected+volunteers:+a+phase+I+study.">Safety and immunogenicity of an intramuscular Helicobacter pylori in noninfected volunteers: a phase I study.</a> Gastroenterology. 135 (3), 787-795 (2008).</li><li>Codolo, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HP-NAP+inhibits+the+growth+of+bladder+cancer+in+mice+by+activating+a+cytotoxic+Th1+response.">HP-NAP inhibits the growth of bladder cancer in mice by activating a cytotoxic Th1 response.</a> Cancer Immunol. Immunother. 61 (1), 31-40 (2012).</li><li>Codolo, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neutrophil-activating+protein+of+Helicobacter+pylori+Th2+inflammation+in+ovalbumin-induced+allergic+asthma.">The neutrophil-activating protein of Helicobacter pylori Th2 inflammation in ovalbumin-induced allergic asthma.</a> Cell. Microbiol. 10 (11), 2355-2363 (2008).</li><li>Del Prete, ., G, , et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunosuppression+of+TH2+responses+in+Trichinella+spiralis+by+Helicobacter+pylori+neutrophil-activating+protein.">Immunosuppression of TH2 responses in Trichinella spiralis by Helicobacter pylori neutrophil-activating protein.</a> J. Allergy Clin. Immunol. 122 (5), 908-913.e5 (2008).</li><li>Tang, R. X., Luo, D. J., Sun, A. H., Yan, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diversity+of+Helicobacter+pylori+in+expression+of+antigens+and+induction+of+antibodies.">Diversity of Helicobacter pylori in expression of antigens and induction of antibodies.</a> World J. Gastroenterol. 14 (30), 4816-4822 (2008).</li><li>Long, M., Luo, J., Li, Y., Zeng, F. Y., Li, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+and+evaluation+of+antibodies+against+neutrophil-activating+protein+of+Helicobacter+pylori+in+patients+with+gastric+cancer.">Detection and evaluation of antibodies against neutrophil-activating protein of Helicobacter pylori in patients with gastric cancer.</a> World J. Gastroenterol. 15 (19), 2381-2388 (2009).</li><li>Song, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+CagA-independent+cluster+of+antigens+related+to+the+risk+of+noncardia+gastric+cancer:+associations+between+Helicobacter+pylori+and+gastric+adenocarcinoma+explored+by+multiplex+serology.">A CagA-independent cluster of antigens related to the risk of noncardia gastric cancer: associations between Helicobacter pylori and gastric adenocarcinoma explored by multiplex serology.</a> Int. J. Cancer. 134 (12), 2942-2950 (2014).</li><li>Kottakis, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Helicobacter+pylori+neutrophil-activating+protein+activates+neutrophils+by+its+C-terminal+region+even+without+dodecamer+formation,+which+is+a+prerequisite+for+DNA+protection--novel+approaches+against+Helicobacter+pylori+inflammation.">Helicobacter pylori neutrophil-activating protein activates neutrophils by its C-terminal region even without dodecamer formation, which is a prerequisite for DNA protection--novel approaches against Helicobacter pylori inflammation.</a> FEBS J. 275 (2), 302-317 (2008).</li><li>Thoreson, A. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differences+in+surface-exposed+antigen+expression+between+Helicobacter+pylori+isolated+from+duodenal+ulcer+patients+and+from+asymptomatic+subjects.">Differences in surface-exposed antigen expression between Helicobacter pylori isolated from duodenal ulcer patients and from asymptomatic subjects.</a> J. Clin. Microbiol. 38 (9), 3436-3441 (2000).</li><li>Wang, C. A., Liu, Y. C., Du, S. Y., Lin, C. W., Fu, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Helicobacter+pylori+neutrophil-activating+protein+promotes+myeloperoxidase+release+from+human+neutrophils.">Helicobacter pylori neutrophil-activating protein promotes myeloperoxidase release from human neutrophils.</a> Biochem. Biophys. Res. Commun. 377 (1), 52-56 (2008).</li><li>Iyer, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduced+surface+area+chromatography+for+flow-through+purification+of+viruses+and+virus+like+particles.">Reduced surface area chromatography for flow-through purification of viruses and virus like particles.</a> J. Chromatogr. A. 1218 (26), 3973-3981 (2011).</li><li>Wongchuphan, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+rabbit+polyclonal+immunoglobulin+G+using+anion+exchangers.">Purification of rabbit polyclonal immunoglobulin G using anion exchangers.</a> Process Biochem. 46 (1), 101-107 (2011).</li><li>Lu, X., Zhao, D., Su, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+hemoglobin+by+ion+exchange+chromatography+in+flow-through+mode+with+PEG+as+an+escort.">Purification of hemoglobin by ion exchange chromatography in flow-through mode with PEG as an escort.</a> Artif. Cells Blood Substit. Immobil. Biotechnol. 32 (2), 209-227 (2004).</li><li>Brooks, S. P., Storey, K. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+and+characterization+of+a+protein+phosphatase+that+dephosphorylates+pyruvate+kinase+in+an+anoxia+tolerant+animal.">Purification and characterization of a protein phosphatase that dephosphorylates pyruvate kinase in an anoxia tolerant animal.</a> Biochem. Mol. Biol. Int. 38 (6), 1223-1234 (1996).</li><li>Gewirtz, A. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Salmonella+typhimurium+translocates+flagellin+across+intestinal+epithelia,+inducing+a+proinflammatory+response.">Salmonella typhimurium translocates flagellin across intestinal epithelia, inducing a proinflammatory response.</a> J. Clin. Invest. 107 (1), 99-109 (2001).</li><li>Levison, P. 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The negative mode batch chromatography with DEAE anion-exchange resins presented here is suitable for purification of recombinant HP-NAP overexpressed in E coli. The pH values of the buffers used in the steps of cell lysis and purification are very critical to ensure the solubility of HP-NAP in E. coli lysates and efficient separation of recombinant HP-NAP from host cell impurities, respectively. Bacterial cells should be lysed at pH 9.0, and the negative purification should be performed at pH 8.0 to ob...

Helicobacter pylori (H. pylori) is a major cause of gastritis and peptic ulcer. This bacterium has also been classified as a carcinogen in humans by the International Agency for Research on Cancer, part of the World Health Organization, in 1994. It has been estimated that the prevalence of H. pylori infection is 70% in the developing countries and 30-40% in the industrialized countries1. Even though the infection rate of H. pylori is decreasing in the industrialized countries, the infection rate of H. pylori in the developing countries is still high2. The standard treatment to eradicate H. pylori infection consists of the administration of a proton pump inhibitor, PPI, and two antibiotics, clarithromycin plus amoxicillin or metronidazole3. However, the rise of antibiotic resistance in H. pylori-related ulcer therapy urges the development of new strategies to prevent or cure the infection. Development of preventive and/or therapeutic vaccination against H. pylori could provide an alternative approach to control H. pylori infection.
Helicobacter pylori neutrophil-activating protein (HP-NAP), a major virulence factor of H pylori, was first identified in water extracts of H. pylori with the ability to activate neutrophils to adhere to endothelial cells and produce reactive oxygen species (ROS)4. Neutrophil infiltration of gastric mucosa found in H. pylori-infected patients with active gastritis may result in inflammation and tissue damage of the stomach. Thus, HP-NAP may play a pathological role by activating neutrophils to induce gastric inflammation, which further causes ulcer or H. pylori-associated gastric diseases. Nevertheless, HP-NAP is a potential candidate for clinical applications5,6. Due to the immunogenic and immunomodulatory properties of HP-NAP, this protein could be used to develop vaccines, therapeutic agents, and diagnostic tools. A clinical trial has been conducted for using recombinant HP-NAP as one of the components of a protein vaccine against H. pylori. This vaccine consists of recombinant HP-NAP, cytotoxin-associated gene A (CagA), and vacuolating cytotoxin A (VacA) proteins formulated with aluminum hydroxide and has further been demonstrated to be safe and immunogenic in humans7. Also, HP-NAP acts as a potent immunomodulator to trigger T helper type 1 (Th1)-polarized immune responses for cancer therapy8 and to down regulate Th2-mediated immune responses elicited by allergic reactions and parasitic infections9,10. As for diagnostics, recombinant HP-NAP-based ELISA has been applied to detect serum antibodies against HP-NAP in H. pylori-infected patients11. One study showed that the level of HP-NAP-specific antibodies in sera from H. pylori-infected patients with gastric cancer was significantly higher than that from patients with chronic gastritis12. Another study also showed that serum antibodies against HP-NAP are associated with the presence of non-cardia gastric adenocarcinoma13. Thus, recombinant HP-NAP-based ELISA may be applied to detect serum antibodies against HP-NAP for prognosis of gastric cancer in H. pylori-infected patients. Taken together, the purified HP-NAP could be further utilized for the prevention, treatment, and prognosis of H. pylori-associated diseases as well as cancer therapy.
Among the several methods used for purification of recombinant HP-NAP expressed in Escherichia coli (E. coli) in its native form reported so far, a second purification step involving gel-filtration chromatography is needed to obtain highly pure HP-NAP14-16. Here, a method using negative mode batch chromatography with diethylaminoethyl (DEAE) ion-exchange resins is described for purification of HP-NAP overexpressed in E. coli with high yield and high purity. This purification technique was based on the binding of host cell proteins and/or impurities other than HP-NAP to the resin. At pH 8.0, almost no other proteins except HP-NAP are recovered from the unbound fraction. This purification approach using DEAE ion-exchange chromatography in negative mode is simple and time saving by allowing purification of recombinant HP-NAP via one-step chromatography through the collection of the unbound fraction. In addition to HP-NAP, several other biomolecules, such as viruses17, Immunoglobulin G (IgG)18, hemoglobin19, protein phosphatase20, and virulence factor flagellin21, have also been reported to be purified by ion-exchange chromatography in negative mode. The negative mode is preferred for ion-exchange chromatography if impurities are the minor components present in the sample subjected to be purified22. The application of negative chromatography in purification of natural or recombinant biomolecules has been recently reviewed23.
The present report provides a step by step protocol for expression of recombinant HP-NAP in E. coli, lysis of the cells, and purification of HP-NAP using negative mode batch chromatography with DEAE ion-exchange resins. If a protein desired for purification is suitable for ion-exchange chromatography in negative mode, the described protocol could also be adapted as a starting point for development of a purification process.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>pET42a-NAP&#160;</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>prepared as described in Supplementary data of Refernce 15&#160; 
			http://www.sciencedirect.com/science/article/pii/S0006291X08018317</td>
		</tr>
		<tr>
			<td>E. coli BL21 (DE3)</td>
			<td>Thermo Fisher Scientific Inc</td>
			<td>C6000-03</td>
			<td>https://www.thermofisher.com/order/catalog/product/C600003</td>
		</tr>
		<tr>
			<td>Kanamycin</td>
			<td>Amresco</td>
			<td>25389-94-0</td>
			<td>http://www.amresco-inc.com/KANAMYCIN-SULFATE-0408.cmsx</td>
		</tr>
		<tr>
			<td>Isopropyl &#946;-D-1-thiogalactopyranoside (IPTG)</td>
			<td>MD Biomedical Inc</td>
			<td>101-367-93-1</td>
			<td>http://www.antibody-antibodies.com/product_det.php?id=238064&#38;supplier=search&#38;name =IPTG%20</td>
		</tr>
		<tr>
			<td>phenylmethylsulfonyl fluoride (PMSF)</td>
			<td>Sigma-Aldrich</td>
			<td>10837091001</td>
			<td>protease inhibitor 
			http://www.sigmaaldrich.com/catalog/product/roche/PMSFRO?lang=en&#38;region=TW</td>
		</tr>
		<tr>
			<td>N-alpha-tosyl-L-lysinyl-chloromethylketone (TLCK)</td>
			<td>Sigma-Aldrich</td>
			<td>T7254</td>
			<td>protease inhibitor 
			http://www.sigmaaldrich.com/catalog/product/sigma/t7254?lang=en&#38;region=TW</td>
		</tr>
		<tr>
			<td>N-tosyl-L-phenylalaninyl-chloromethylketone (TPCK)</td>
			<td>Sigma-Aldrich</td>
			<td>T4376</td>
			<td>protease inhibitor 
			http://www.sigmaaldrich.com/catalog/product/sigma/t4376?lang=en&#38;region=TW</td>
		</tr>
		<tr>
			<td>Bio-Rad protein assay dye reagent concentrate</td>
			<td>Bio&#8208;Rad</td>
			<td>500-0006</td>
			<td>for protein quantitation 
			http://www.bio-rad.com/en-us/sku/5000006-bio-rad-protein-assay-dye-reagent-concentrate</td>
		</tr>
		<tr>
			<td>Protein standard (bovine serum albumin)</td>
			<td>Sigma-Aldrich</td>
			<td>P5619&#160;</td>
			<td>a standard protein for Bio-Rad Protein Assay 
			http://www.sigmaaldrich.com/catalog/product/fluka/p5619?lang=en&#38;region=TW</td>
		</tr>
		<tr>
			<td>DEAE&#8211;Sephadex &#160;A-25 chloride form</td>
			<td>Sigma-Aldrich</td>
			<td>A25120</td>
			<td>http://www.sigmaaldrich.com/catalog/product/sigma/a25120?lang=en&#38;region=TW</td>
		</tr>
		<tr>
			<td>Spectrum/Por dialysis tubing</td>
			<td>Spectrum Laboratories</td>
			<td>132720</td>
			<td>with molecular weight cutoff of 14 kDa 
			http://www.spectrumlabs.com/dialysis/RCtubing.html?Pn=132720;</td>
		</tr>
		<tr>
			<td>Acrodisc&#174; units with Mustang&#174; E membrane</td>
			<td>Pall</td>
			<td>MSTG25E3</td>
			<td>for endotoxin removal; operated at flow rates ranging from 1 to 4 ml/min 
			http://www.pall.com/main/laboratory/product.page?id=19992</td>
		</tr>
		<tr>
			<td>mouse monoclonal antibody MAb 16F4</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>raised against the purified HP-NAP of H. pylori strain NCTC 11637 as described in Refernce 23;&#160; A gift from Drs. Evanthia Galanis and Ianko D. Iankov at Mayo Clinic, USA 
			http://www.sciencedirect.com/science/article/pii/S0264410X10017585</td>
		</tr>
		<tr>
			<td>HiLoad 16/600 Superdex 200 pg</td>
			<td>GE Healthcare Life Sciences</td>
			<td>28989335</td>
			<td>for gel filtration chromatography 
			http://www.gelifesciences.com/webapp/wcs/stores/servlet/productById/en/GELifeSciences-tw/28989335</td>
		</tr>
		<tr>
			<td>PlusOne silver staining kit, protein</td>
			<td>GE Healthcare Life Sciences</td>
			<td>17-1150-01</td>
			<td>http://www.gelifesciences.com/webapp/wcs/stores/servlet/productById/en/GELifeSciences-tw/17115001</td>
		</tr>
		<tr>
			<td>Ficoll-Paque PLUS</td>
			<td>GE Healthcare Life Sciences</td>
			<td>17-1440-02</td>
			<td>for density gradient centrifugation to purify human neutrophils 
			http://www.gelifesciences.com/webapp/wcs/stores/servlet/catalog/en/GELifeSciences-tw/products/AlternativeProductStructure _16963/17144002</td>
		</tr>
		<tr>
			<td>Flat bottom 96-well white plate</td>
			<td>Thermo Fisher Scientific Inc</td>
			<td>236108</td>
			<td>http://www.thermoscientific.com/en/product/nunc-f96-microwell-black-white-polystyrene-plate.html</td>
		</tr>
		<tr>
			<td>Luminol</td>
			<td>Sigma-Aldrich</td>
			<td>A8511</td>
			<td>protected from light 
			http://www.sigmaaldrich.com/catalog/product/sigma/a8511?lang=en&#38;region=TW</td>
		</tr>
		<tr>
			<td>Expand &#160;long template PCR system</td>
			<td>Sigma-Aldrich</td>
			<td>11681834001</td>
			<td>source of High Fidelity PCR enzyme mix 
			http://www.sigmaaldrich.com/catalog/product/roche/elongro?lang=en&#38;region=TW</td>
		</tr>
		<tr>
			<td>Dpn I</td>
			<td>New England Biolabs</td>
			<td>R0176S</td>
			<td>https://www.neb.com/products/r0176-dpni</td>
		</tr>
		<tr>
			<td>Xho I</td>
			<td>New England Biolabs</td>
			<td>R0146S</td>
			<td>https://www.neb.com/products/r0146-xhoi</td>
		</tr>
		<tr>
			<td>E. coli DH5&#945;</td>
			<td>Thermo Fisher Scientific Inc</td>
			<td>18265-017</td>
			<td>https://www.thermofisher.com/order/catalog/product/18265017</td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Product Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td> 
			&#160;</td>
		</tr>
		<tr>
			<td>U-2800 double beam UV/VIS spectrophotometer</td>
			<td>Hitachi&#160;</td>
			<td>N/A</td>
			<td>out of market and upgraded to a new model 
			http://hitachi-hta.com/products/life-sciences-chemical-analysis/uvvisible-spectrophotometers</td>
		</tr>
		<tr>
			<td>EmulsiFlex-C3 high pressure homogenizer</td>
			<td>Avestin Inc</td>
			<td>C315320</td>
			<td>http://www.avestin.com/English/c3page.html</td>
		</tr>
		<tr>
			<td>Hitachi Koki himac CP80WX general ultracentrifuge</td>
			<td>Hitachi Koki Co</td>
			<td>90106401</td>
			<td>for separation of the soluble and insoluble protein fractions from E. coli lysates 
			http://centrifuges.hitachi-koki.com/products/ultra/cp_wx/cp_wx.html</td>
		</tr>
		<tr>
			<td>&#196;KTA FPLC</td>
			<td>GE Healthcare Life Sciences</td>
			<td>18-1900-26</td>
			<td>for gel filtration chromatography 
			http://www.gelifesciences.com/webapp/wcs/stores/servlet/productById/en/GELifeSciences-tw/18190026</td>
		</tr>
		<tr>
			<td>Aviv model 62ADS CD spectrophotometer</td>
			<td>Aviv Biomedical</td>
			<td>N/A</td>
			<td>out of market and upgraded to a new model 
			http://www.avivbiomedical.com/circular.php</td>
		</tr>
		<tr>
			<td>LAS-3000 imaging system</td>
			<td>Fujifilm</td>
			<td>N/A</td>
			<td>discontinued and replaced 
			http://www.gelifesciences.com/webapp/wcs/stores/servlet/productById/en/GELifeSciences-tw/28955810</td>
		</tr>
		<tr>
			<td>Wallac 1420 (Victor2) multilabel counter</td>
			<td>Perkin-Elmer</td>
			<td>1420-018</td>
			<td>for chemiluminescence detection 
			http://www.perkinelmer.com/catalog/product/id/1420-018</td>
		</tr>
	</tbody>
</table>

one-step negative chromatographic purification of helicobacter pylori neutrophil-activating protein overexpressed in escherichia coli in batch mode

Helicobacter pylori neutrophil-activating protein (HP-NAP) is a major virulence factor of Helicobacter pylori (H. pylori). It plays a critical role in H. pylori-induced gastric inflammation by activating several innate leukocytes including neutrophils, monocytes, and mast cells. The immunogenic and immunomodulatory properties of HP-NAP make it a potential diagnostic and vaccine candidate for H. pylori and a new drug candidate for cancer therapy. In order to obtain substantial quantities of purified HP-NAP used for its clinical applications, an efficient method to purify this protein with high yield and purity needs to be established.
In this protocol, we have described a method for one-step negative chromatographic purification of recombinant HP-NAP overexpressed in Escherichia coli (E. coli) by using diethylaminoethyl (DEAE) ion-exchange resins (e.g., Sephadex) in batch mode. Recombinant HP-NAP constitutes nearly 70% of the total protein in E. coli and is almost fully recovered in the soluble fraction upon cell lysis at pH 9.0. Under the optimal condition at pH 8.0, the majority of HP-NAP is recovered in the unbound fraction while the endogenous proteins from E. coli are efficiently removed by the resin.
This purification method using negative mode batch chromatography with DEAE ion-exchange resins yields functional HP-NAP from E. coli in its native form with high yield and purity. The purified HP-NAP could be further utilized for the prevention, treatment, and prognosis of H. pylori-associated diseases as well as cancer therapy.

The schematic diagram of the experimental procedure of negative purification of recombinant HP-NAP expressed in E. coli by using DEAE ion-exchange resins in batch mode is shown in Figure 1. This purification technique is based on the binding of host cell proteins and/or impurities other than HP-NAP to the resin. At pH 8.0, almost no other proteins except HP-NAP in its native form are recovered from the unbound fraction (Figure 2A and B</s...

Watch this Scientific Journal Video about One-step Negative Chromatographic Purification of Helicobacter pylori Neutrophil-activating Protein Overexpressed in Escherichia coli in Batch Mode at JoVE.co

One-step Negative Chromatographic Purification of Helicobacter pylori Neutrophil-activating Protein Overexpressed in Escherichia coli in Batch Mode

A high yield method for one-step negative purification of recombinant Helicobacter pylori neutrophil-activating protein (HP-NAP) overexpressed in Escherichia coli by using diethylaminoethyl resins in batch mode is described. HP-NAP purified by this method is beneficial for the development of vaccines, drugs, or diagnostics for H. pylori-associated diseases.

One-step Negative Chromatographic Purification of Helicobacter pylori Neutrophil-activating Protein Overexpressed in Escherichia coli in Batch Mode

Helicobacter pylori neutrophil-activating protein (HP-NAP) is a major virulence factor of Helicobacter pylori (H. pylori). It plays a critical role in H. ...

The overall goal of this purification is to yield functional Helicobacter pylori Neutrophil-activating protein or HP-NAP in its native form with high purity and high yield using negative mode batch chromatography with di-ethyl amino-ethyl ion exchange resin. The main advantage of this technique is that HP-NAP can be purified in its native form in one step with high purity and high yield. Negative purification of HP-NAP starts with a batch binding procedure in which the soluble protein fraction from bacterial lysates is added to DEAE resin.The mixture is incubated to allow wholesale proteins to bind to the resin. HP-NAP present in the unbound fraction is then obtained by centrifugation of gravity flow. The implications of this technique is 10:1 prevention treatment and prognostic of Helicobacter pylori associated diseases as well as cancer therapy.Because of the immunogenic and immunomodulatory properties of HP-NAP. Generally, individuals new to this method will struggle. Because HP-NAP easily aggregates during the sterilization.Demonstrating the procedure will be Zhi-Wei Hong, a graduate student from our lab. Working at four degrees Celsius, we suspend 50 milliliters of the cell palate prepared as described in the text protocol in 20 milliliters of low salt, tris-buffer at pH 9.0 with protease inhibitor mixture. It's critical to keep sample at the four degrees Celsius to allow the procedure to prevent the protein aggregation.Disrupt the bacterial cells by passing the bacterial suspension through a high-pressure homogenizer operated at a range of 15, 000 to 20, 000 PSI for seven times at four degrees Celsius. After lysates baterializes, it should be centrifuged immediately. Transfer homogenized samples to a centrifuge tube.Immediately centrifuge the cell-lysate at 30, 000 times G at four degrees Celsius for one hour to separate the soluble and insoluble protein fractions by using an ultra-centrifuge. Following centrifugation, transfer the supernatant as the soluble protein fraction to a beaker. Measure the protein concentration of the soluble protein fraction by the Bradford method using a commercial kit with bovine serum albumin as the standard according to the manufacturer's instructions.Then add 177.6 microliters of one normal HCl into 20 milliliters of the soluble protein fraction to adjust its pH value from pH 9.0 to pH 8.0. Add 20 millimeter Tris-HCl, pH 8.0, 50 milliliter sodium chloride to the protein solution to result in a final protein concentration of 0.5 milligrams per milliliter. To prepare 15 milliliters of DEAE resin, suspend 0.6 grams of DEAE resin dry powder in 30 milliliters of Tris-HCl buffer at room temperature for at least one day.Centrifuge the resin at 10, 000 times G at four degrees Celsius for one minute and then remove and discard the supernatant. Then add 15 milliliters of Tris-HCl buffer. After repeating the centrifugation resuspension steps four more times, store the 15 milliliters of settled resin at four degrees Celsius for subsequent use.Working at four degrees Celsius, add 45 milliliters of the prepared soluble proteins to milliliters of the resin and transfer to a 100 milliliter beaker with stir bar. Stir the protein resin slurry using a stir plate at four degrees Celsius for one hour. Next, pour the protein resin slurry into a plastic or a glass column fitted with a stopcock and allow the resin to settle under gravity.Open the stopcock to allow the protein solution to run through the column by gravity flow until the liquid level in the column is just above the resin. Collect the flow through as the unbound fraction which contains the purified neutrophil-activating protein. Add 15 milliliters of the ice-cold Tris-HCl buffer into the column.Open the stopcock again to allow the wash buffer to run through the column by gravity flow until the liquid level in the column is just above the resin. Collect the flow through as the wash fraction. Repeat washing with ice-cold buffer four more times to collect the additional wash fractions.Then add 15 milliliters of ice-cold 20 millimeter Tris-HCl pH 8.0, one molar sodium chloride into the column. Collect the flow through as the elution fractions as before. Repeat the elution steps four more times to collect the additional elution fractions.The effect of pH on solubility of HP-NAP in E.coli lysate are shown here. The amount of HP-NAP detected in this soluble fraction was markedly increased at pH 7.5 to 9.5. Recombinant HP-NAP was almost fully recovered in the soluble fraction upon cell lysis at pH 9.0.Here, the effect of pH on negative purification of recombinant HP-NAP expressed in E.coli by DEAE resins in batch mode are shown. At pH 8.0, only a little amount of HP-NAP was present in the elution fraction. The amount of HP-NAP present in the unbound fractions was the highest at pH 8.0.The optimized amount of proteins loaded onto the DEAE resin is 1.5 milligrams of protein per milliliter of resin for achieving maximum capacity of the resin to absorb the impurities from E.coli. At pH 8.0, very few proteins other than HP-NAP in its native form are recovered in the unbound fraction using DEAE resins in batch mode. The purity of HP-NAP was higher than 95 percent.The purified HP-NAP folds into a multimer with a secondary structure of alpha-helix as revealed by the gelifiltration chromotogram and the far UV circular dichroism spectrum. A luminal dependent chemiluminescence assay reveals that the purified HP-NAP is able to trigger the production of reactive oxygen species by neutrophiles. Once mastered, these techniques can be done within five hours if it is performed properly.After watching this video you should have a good understanding of how to purify functional HP-NAP in its native form with high yield and purity using negative mode batch chromotography with DEAE and exchange resin. While attempting this procedure, it's important to remember to use buffers at the appropriate pH in the step of sterilizes in the batch chromotography. We first had the idea for this method when we tried to apply other chromotographic approaches instead of filtration to purify HP-NAP in its native form.Though this method is designed to appeal by recombinant HP-NAP expressed in E.coli. It can also be applied to other bacterial expression systems such as per-sida sep-tidas. Visual demonstration of this measure is quick code.Plus the step of sterilizes and batch chromotography are difficult to learn. Because these steps must be carried out at the four degrees Celsius without any time delay. If a protein designed for purification is suitable for our exchange chromotography in negative mode, this procedure could also be adapted as a starting point for the development of purification process.After its development, this technique paved the way for researchers in the field of clinical research to explore the possibility of using HP-NAP in cancer therapy as well as the development of vaccines, drugs, and the diagnostics for Helicobacter pylori associated disease.

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Research

JoVE Journal

Immunology and Infection

9.6K vistas.  National Tsing Hua University. The overall goal of this purification is to yield functional Helicobacter pylori Neutrophil-activating protein or HP-NAP in its native form with high purity and high yield using negative mode batch chromatography with di-ethyl amino-ethyl ion exchange resin. The main advantage of this technique is that HP-NAP can be purified in its native form in one step with high purity and high yield. Negative purification of HP-NAP starts with a batch binding procedure in which the soluble protein fractio...

Video: One-step Negative Chromatographic Purification of Helicobacter pylori Neutrophil-activating Protein Overexpressed in Escherichia coli in Batch Mode