Nos gustaría agradecer la asistencia técnica de Inés Racke.

Parte 1: Preparación de la solución de tinción CBB <ol><li> 60-80 mg de CBB G-250 se disuelven en 1 litro de agua bidestilada por agitación durante 2-4 horas. Por último, 3 ml de HCl concentrado, se añade a la solución de color azul oscuro con agitación durante un minuto y se almacena en la oscuridad para su uso posterior. La solución se puede almacenar durante varias semanas hasta varios meses sin perder su eficacia manchas. </li><li> HCl concentrado debe ser manejado con el cuidado habitual und usada bajo una campana de humos. La solución final será aproximadamente a pH 2, por lo que se debe utilizar guantes y cualquier contacto con la piel debe ser evitado. </li></ol> Parte 2: SDS-PAGE <ol><li> Alícuotas apropiadas de muestras de proteínas se mezclan con tampón de carga a una concentración final de tampón de carga 1x. Usamos tampón de carga 2x 125mm Tris/H3PO4 (pH 7,5 a 25 ° C), 2 mM EDTA, SDS al 4%, DTT 200 mM, azul de bromofenol 0,02% y el 50% de glicerol. Otros tampones de carga para SDS-PAGE se puede usar también. </li><li> Las muestras de proteínas se calientan durante unos 5 minutos antes de la carga. Mientras tanto, la cámara de electroforesis en gel se prepara para la carrera. Usamos NuPAGE prefabricados 12.04% © Bis-Tris geles (Invitrogen) en un SureLock XCell ® Mini-Cell (Invitrogen), con economía de mercado-buffer como el funcionamiento de amortiguación, pero cualquier otro gel y el sistema de electroforesis se puede utilizar también. </li><li> Las muestras de proteínas se cargan en el gel y la electroforesis en una duración de 50 minutos a 220V. </li></ol> Parte 3: La tinción del gel <ol><li> El gel cassette está desmontada y el gel en una caja para los pasos posteriores de lavado. </li><li> Cerca de 100 ml de agua bidestilada se añade el gel y se calienta en el microondas durante 30 segundos. Calefacción debe detenerse antes de la ebullición se produce. La caja con el gel se coloca en un agitador durante 3-5 min. y este paso de lavado se repite dos veces con agua fresca. </li><li> Suficiente solución de tinción CBB se añade a cubrir el gel en la caja y la caja se calienta en el microondas durante 10 segundos. sin hervir. La caja con el gel se coloca en un agitador para el acabado de la tinción. Ya después de 1 minuto, las bandas de proteínas se puede observar, después de 15-30 min. la tinción es lo suficientemente fuerte como en la mayoría de los casos. </li><li> La solución colorante se escurre y 50-100 ml de agua bidestilada, se añade con el fin de destain aún más la luz de fondo azul del gel en un agitador. El agua puede ser sustituida por agua dulce para la decoloración más si es necesario. </li><li> El gel puede ser escaneado, fotografiado o secas para almacenamiento a largo plazo </li></ol> Parte 4: Resultados del representante: Ver fig. 1 para un gel teñido correctamente siguiendo el procedimiento descrito. Ver fig. 2 para un gel que no se ha lavado el tiempo suficiente antes de la tinción y coloración residual SDS inhibe eficiente. Tenga en cuenta que los carriles marcador (*) contienen la misma cantidad de proteínas marcadoras. <img src="/files/ftp_upload/1350/Fig1.png" alt="" /> Fig. 1: Representante manchadas gel después de cargar las muestras de una purificación de proteínas (*: marcador de peso molecular). <img src="/files/ftp_upload/1350/Fig2.png" alt="" /> Fig. 2: CBB gel de colores que no se ha lavado el tiempo suficiente antes de la tinción CBB. Las bandas de proteínas aparecen más débiles (nótese que el carril * marcador contiene la misma cantidad de proteínas como en la fig. 1).

<ol>
	<li>Wondrak, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Process+for+fast+visualization+of+protein.">Process for fast visualization of protein.</a> US patent. , (2001).</li><li>Wondrak, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solution+for+fast+visualization+of+protein.">Solution for fast visualization of protein.</a> US patent. , (2001).</li></ol>

No hay conflicto de intereses. El procedimiento descrito anteriormente fue publicado originalmente en la solicitud de patente por EM Wondrak (ver ref.).

<ul><li> Los pasos de lavado son fundamentales para la tinción eficiente de las proteínas. Una reducción del tiempo de lavado por debajo de 2 min o disminución del volumen de agua (&lt;50 ml) puede dar lugar a bandas de proteínas pálido azul, muy probablemente debido a una mayor cantidad de residuos SDS en el gel. </li><li> Si las proteínas van a ser analizados por espectrometría de masas, los pasos de calentamiento en el horno de microondas debe ser omitido, el tiempo para el lavado del gel extendido a unos 10 minutos en cada paso y el...

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Coomassie Brilliant Blue G-250</td>
<td>&nbsp;</td>
<td>AppliChem</td>
<td>A3480</td>
<td>any other CBB G-250 could be used as well</td>
</tr>
<tr>
<td>Concentrated HCl</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

staining of proteins in gels with coomassie g-250 without organic solvent and acetic acid

En los protocolos clásicos de proteínas tinción con Coomassie Brilliant Blue (CBB), las soluciones con un alto contenido de disolventes orgánicos tóxicos e inflamables (metanol, etanol o 2-propanol) y ácido acético se utilizan para la fijación, tinción y decoloración de las proteínas en un gel de SDS después -PAGE. Para acelerar el procedimiento, el calentamiento de la solución de tinción en el horno de microondas por un corto período de tiempo se utiliza con frecuencia. Esto usualmente resulta en la evaporación de metanol tóxicos o peligrosos, etanol o 2-propanol y un fuerte olor a ácido acético en el laboratorio que deben evitarse por motivos de seguridad. En un protocolo publicado originalmente en dos solicitudes de patente por EM Wondrak (US2001046709 (A1), US6319720 (B1)), una composición alternativa de la solución de tinción se describe en la que no solvente orgánico o ácido se utiliza. El CBB se disuelve en agua bidestilada (60-80mg de CBB G-250 por litro) y 35 mM HCl se agrega como el único compuesto otros en la solución de tinción. El CBB staning del gel se realiza después de SDS-PAGE y minuciosamente del gel en agua bidestilada. Al calentar el gel durante el lavado y la tinción de pasos, el proceso puede terminar más rápido y no compunds tóxicos o peligrosos se evapora. La tinción de las proteínas ocurre ya dentro de 1 minuto después de calentar el gel en solución de tinción y se desarrolla completamente después de 15-30 minutos con un fondo azul que es un poco desteñido por completo por el lavado prolongado del gel teñido con agua bidestilada, sin afectar a la proteína manchado bandas.

Watch this Scientific Journal Video about Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid at JoVE.com

Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid

Un protocolo corto para la tinción de proteínas con Coomassie Brilliant Blue (CBB) G-250 en geles de poliacrilamida se describe sin el uso de disolventes orgánicos o en ácido acético como en los procedimientos clásicas de tinción con CBB.

Tinción de las proteínas en geles con Coomassie G-250, sin ácido disolvente orgánico y el acético

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents ...

staining-proteins-gels-with-coomassie-g-250-without-organic-solvent

Research

JoVE Journal

Biology

52.8K vistas.  EMBL Heidelberg. Un protocolo corto para la tinción de proteínas con Coomassie Brilliant Blue (CBB) G-250 en geles de poliacrilamida se describe sin el uso de disolventes orgánicos o en ácido acético como en los procedimientos clásicas de tinción con CBB.

Video: Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid

Staining Proteins in Gels

Following separation by electrophoretic methods, proteins in a gel can be detected by several staining methods. This unit describes protocols for detecting proteins by four popular methods. Coomassie blue staining is an easy and rapid method. Silver staining, while more time consuming, is considerably more sensitive and can thus be used to detect smaller amounts of protein. Fluorescent staining is a popular alternative to traditional staining procedures, mainly because it is more sensitive than Coomassie staining, and is often as sensitive as silver staining. Staining of proteins with SYPRO Orange and SYPRO Ruby are also demonstrated here.

Following separation by electrophoretic methods, proteins in a gel can be detected by several staining methods. Staining of proteins with Coomassie Blue, Silver Staining, SYPRO Orange, SYPRO Ruby are demonstrated in this video.

Tinción de proteínas en geles de

Following separation by electrophoretic methods, proteins in a gel can be detected by several staining methods. This unit describes protocols for ...

Investigación

Biología

Fast and Sensitive Colloidal Coomassie G-250 Staining for Proteins in Polyacrylamide Gels

Coomassie Brilliant Blue (CBB) is a dye commonly used for the visualization of proteins separated by SDS-PAGE, offering a simple staining procedure and high quantitation. Furthermore, it is completely compatible with mass spectrometric protein identification. But despite these advantages, CBB is regarded to be less sensitive than silver or fluorescence stainings and therefore rarely used for the detection of proteins in analytical gel-based proteomic approaches.
Several improvements of the original Coomassie protocol1 have been made to increase the sensitivity of CBB. Two major modifications were introduced to enhance the detection of low-abundant proteins by converting the dye molecules into colloidal particles: In 1988, Neuhoff and colleagues applied 20% methanol and higher concentrations of ammonium sulfate into the CBB G-250 based staining solution2, and in 2004 Candiano et al. established Blue Silver using CBB G-250 with phosphoric acid in the presence of ammonium sulfate and methanol3. Nevertheless, all these modifications just allow a detection of approximately 10 ng protein. A widely fameless protocol for colloidal Coomassie staining was published by Kang et al. in 2002 where they modified Neuhoff's colloidal CBB staining protocol regarding the complexing substances. Instead of ammonium sulfate they used aluminum sulfate and methanol was replaced by the less toxic ethanol4. The novel aluminum-based staining in Kang's study showed superior sensitivity that detects as low as 1 ng/band (phosphorylase b) with little sensitivity variation depending on proteins.
Here, we demonstrate application of Kang's protocol for fast and sensitive colloidal Coomassie staining of proteins in analytical purposes. We will illustrate the quick and easy protocol using two-dimensional gels routinely performed in our working group.

This video shall popularize a colloidal Coomassie G-250 staining protocol according to Kang et al. for the detection of average 4 ng protein in gels. The staining is completed within 2 hours and without any effort. We routinely use Kang's protocol for analytical purposes in gel-based proteomics.

Rápido y sensible coloidal Coomassie G-250 La tinción de proteínas en geles de poliacrilamida

Coomassie Brilliant Blue (CBB) is a dye commonly used for the visualization of proteins separated by SDS-PAGE, offering a simple staining procedure and ...

Profiling of Methyltransferases and Other S-adenosyl-L-homocysteine-binding Proteins by Capture Compound Mass Spectrometry (CCMS)

There is a variety of approaches to reduce the complexity of the proteome on the basis of functional small molecule-protein interactions such as affinity chromatography 1 or Activity Based Protein Profiling 2. Trifunctional Capture Compounds (CCs, Figure 1A) 3 are the basis for a generic approach, in which the initial equilibrium-driven interaction between a small molecule probe (the selectivity function, here S-adenosyl-L-homocysteine, SAH, Figure 1A) and target proteins is irreversibly fixed upon photo-crosslinking between an independent photo-activable reactivity function (here a phenylazide) of the CC and the surface of the target proteins. The sorting function (here biotin) serves to isolate the CC - protein conjugates from complex biological mixtures with the help of a solid phase (here streptavidin magnetic beads). Two configurations of the experiments are possible: "off-bead" 4 or the presently described "on-bead" configuration (Figure 1B). The selectivity function may be virtually any small molecule of interest (substrates, inhibitors, drug molecules).
S-Adenosyl-L-methionine (SAM, Figure 1A) is probably, second to ATP, the most widely used cofactor in nature 5, 6. It is used as the major methyl group donor in all living organisms with the chemical reaction being catalyzed by SAM-dependent methyltransferases (MTases), which methylate DNA 7, RNA 8, proteins 9, or small molecules 10. Given the crucial role of methylation reactions in diverse physiological scenarios (gene regulation, epigenetics, metabolism), the profiling of MTases can be expected to become of similar importance in functional proteomics as the profiling of kinases. Analytical tools for their profiling, however, have not been available. We recently introduced a CC with SAH as selectivity group to fill this technological gap (Figure 1A).
SAH, the product of SAM after methyl transfer, is a known general MTase product inhibitor 11. For this reason and because the natural cofactor SAM is used by further enzymes transferring other parts of the cofactor or initiating radical reactions as well as because of its chemical instability 12, SAH is an ideal selectivity function for a CC to target MTases. Here, we report the utility of the SAH-CC and CCMS by profiling MTases and other SAH-binding proteins from the strain DH5&alpha; of Escherichia coli (E. coli), one of the best-characterized prokaryotes, which has served as the preferred model organism in countless biochemical, biological, and biotechnological studies. Photo-activated crosslinking enhances yield and sensitivity of the experiment, and the specificity can be readily tested for in competition experiments using an excess of free SAH.

Profiling of Methyltransferases and Other S-adenosyl-L-homocysteine-binding Proteins by Capture Compound Mass Spectrometry CCMS

Capture Compounds are trifunctional small molecules to reduce the complexity of the proteome by functional reversible small molecule-protein interaction followed by photo-crosslinking and purification. Here we use a Capture Compound with S-adenosyl-L-homocysteine-binding as selectivity function to isolate methyltransferases from an Escherichia coli whole cell lysate and identify them by MS.

Perfiles de metiltransferasas y Otros S-Adenosil- L-Homocisteína proteínas que se unen mediante espectrometría de masas de captura compuesto (MCP)

There is a variety of approaches to reduce the complexity of the proteome on the basis of functional small molecule-protein interactions such as affinity ...

Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling

Two electrode voltage clamp electrophysiology (TEVC) is a powerful tool to investigate the mechanism of ion transport1 for a wide variety of membrane proteins including ion channels2, ion pumps3, and transporters4. Recent developments have combined site-specific fluorophore labeling alongside TEVC to 
concurrently examine the conformational dynamics at specific residues and function of these proteins on the surface of single cells.
We will describe a method to study the conformational dynamics of membrane proteins by simultaneously monitoring fluorescence and current changes using voltage-clamp fluorometry. This approach can be used to examine the molecular motion of membrane proteins site-specifically following cysteine replacement and site-directed fluorophore labeling5,6. Furthermore, this method provides an approach to determine distance constraints between specific residues7,8. 
This is achieved by selectively attaching donor and acceptor fluorophores to two mutated cysteine residues of interest.
In brief, these experiments are performed following functional expression of the desired protein on the surface of Xenopus leavis oocytes. The large surface area of these oocytes enables facile functional measurements and a robust fluorescence signal5. It is also possible to readily change the extracellular conditions such as pH, ligand or cations/anions, which can provide further information on the mechanism of membrane proteins4. Finally, recent developments 
have also enabled the manipulation of select internal ions following co-expression with a second protein9.
Our protocol is described in multiple parts. First, cysteine scanning mutagenesis proceeded by fluorophore labeling is completed at residues located at the interface of the transmembrane and extracellular domains. Subsequent experiments are designed to identify residues which demonstrate large changes in fluorescence intensity (&lt;5%)3 upon a conformational change of the protein. Second, these changes in fluorescence intensity are compared to the kinetic parameters of 
the membrane protein in order to correlate the conformational dynamics to the function of the protein10. This enables a rigorous biophysical analysis of the molecular motion of the target protein. Lastly, two residues of the holoenzyme can be labeled with a donor and acceptor fluorophore in order to determine distance constraints using donor photodestruction methods. It is also possible to monitor the relative movement of protein subunits following labeling with a donor and acceptor fluorophore.

Examining the Conformational Dynamics of Membrane Proteins in situ with Site-directed Fluorescence Labeling

We will describe a method which measures the kinetics of ion transport of membrane proteins alongside site-specific analysis of conformational changes using fluorescence on single cells. This technique is adaptable to ion channels, transporters and ion pumps and can be utilized to determine distance constraints between protein subunits.

Examinar la dinámica conformacional de las proteínas de membrana In situ Sitio-dirigida con fluorescencia de etiquetado

Two electrode voltage clamp electrophysiology (TEVC) is a powerful tool to investigate the mechanism of ion transport1 for a wide variety of membrane ...

High-Throughput Measurement and Classification of Organic P in Environmental Samples

Many types of organic phosphorus (P) molecules exist in environmental samples1. Traditional P measurements do not detect these organic P compounds since they do not react with colorimetric reagents2,3. Enzymatic hydrolysis (EH) is an emerging method for accurately characterizing organic P forms in environmental samples4,5. This method is only trumped in accuracy by Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy (31P-NMR) -a method that is expensive and requires specialized technical training6. We have adapted an enzymatic hydrolysis method capable of measuring three classes of phosphorus (monoester P, diester P and inorganic P) to a microplate reader system7. This method provides researchers with a fast, accurate, affordable and user-friendly means to measure P species in soils, sediments, manures and, if concentrated, aquatic samples. This is the only high-throughput method for measuring the forms and enzyme-lability of organic P that can be performed in a standard laboratory. The resulting data provides insight to scientists studying system nutrient content and eutrophication potential.

This protocol describes a high-throughput method of enzymatic hydrolysis that utilizes a microplate reader to measure and classify soil phosphorus as P monoesters, P diesters and inorganic P. Up to 96 samples can be measured at one time in a standard laboratory.

Alto Rendimiento de medición y clasificación de P orgánico en las muestras ambientales

Many types of organic phosphorus (P) molecules exist in environmental samples1.  Traditional P measurements do not detect these organic P compounds since ...

Quantification of Proteins Using Peptide Immunoaffinity Enrichment Coupled with Mass Spectrometry

There is a great need for quantitative assays in measuring proteins. Traditional sandwich immunoassays, largely considered the gold standard in quantitation, are associated with a high cost, long lead time, and are fraught with drawbacks (e.g. heterophilic antibodies, autoantibody interference, 'hook-effect').1 An alternative technique is affinity enrichment of peptides coupled with quantitative mass spectrometry, commonly referred to as SISCAPA (Stable Isotope Standards and Capture by Anti-Peptide Antibodies).2 In this technique, affinity enrichment of peptides with stable isotope dilution and detection by selected/multiple reaction monitoring mass spectrometry (SRM/MRM-MS) provides quantitative measurement of peptides as surrogates for their respective proteins. SRM/MRM-MS is well established for accurate quantitation of small molecules 3, 4 and more recently has been adapted to measure the concentrations of proteins in plasma and cell lysates.5-7 To achieve quantitation of proteins, these larger molecules are digested to component peptides using an enzyme such as trypsin. One or more selected peptides whose sequence is unique to the target protein in that species (i.e. "proteotypic" peptides) are then enriched from the sample using anti-peptide antibodies and measured as quantitative stoichiometric surrogates for protein concentration in the sample. Hence, coupled to stable isotope dilution (SID) methods (i.e. a spiked-in stable isotope labeled peptide standard), SRM/MRM can be used to measure concentrations of proteotypic peptides as surrogates for quantification of proteins in complex biological matrices. The assays have several advantages compared to traditional immunoassays. The reagents are relatively less expensive to generate, the specificity for the analyte is excellent, the assays can be highly multiplexed, enrichment can be performed from neat plasma (no depletion required), and the technique is amenable to a wide array of proteins or modifications of interest.8-13 In this video we demonstrate the basic protocol as adapted to a magnetic bead platform.

Stable Isotope Standards and Capture by Anti-Peptide Antibodies (SISCAPA) couples affinity enrichment of peptides with stable isotope dilution mass spectrometry (MRM-MS) to provide quantitative measurement of peptides as surrogates for their respective proteins. Here we describe the protocol using magnetic particles in a partially automated format.

La cuantificación de proteínas mediante el enriquecimiento de inmunoafinidad péptido acoplado a espectrometría de masas

There is a great need for quantitative assays in measuring proteins. Traditional sandwich immunoassays, largely considered the gold standard in ...

Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups

Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9n- (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry.3-6 Notable milestones are the oxidative coupling of Ge94- clusters to oligomers and infinite chains,7-19 their metallation,14-16,20-25 capping by transition-metal organometallic fragments,26-34 insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization,35-47 addition of main-group organometallic fragments as exo-bonded substituents,48-50 and functionalization with various organic residues by reactions with organic halides and alkynes.51-58 
This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge94- clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC&equiv;CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2]2-. For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left undisturbed for a few days, the so-layered solutions produced orange crystalline blocks of [K(18-crown-6)]2[Ge9(HCCH2)2]&bull;en which were characterized by single-crystal X-ray diffraction. 
The process highlights standard reaction techniques, work-up, and analysis towards functionalized deltahedral Zintl clusters. It is hoped that it will help towards further development and understanding of these compounds in the community at large.

We present the high-temperature synthesis of intermetallic precursors K4Ge9, their dissolution in ethylenediamine to form Ge94- deltahedral Zintl ions, and the reaction of the clusters with alkynes to form organo-Zintl ions. The latter are characterized by electrospray mass spectrometry in solutions and by single-crystal X-ray diffraction in the solid state.

Síntesis de Deltahedral de nueve átomos de germanio Zintl iones y su funcionalización con grupos orgánicos

Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 ...

Analyzing and Building Nucleic Acid Structures with 3DNA

The 3DNA software package is a popular and versatile bioinformatics tool with capabilities to analyze, construct, and visualize three-dimensional nucleic acid structures. This article presents detailed protocols for a subset of new and popular features available in 3DNA, applicable to both individual structures and ensembles of related structures. Protocol 1 lists the set of instructions needed to download and install the software. This is followed, in Protocol 2, by the analysis of a nucleic acid structure, including the assignment of base pairs and the determination of rigid-body parameters that describe the structure and, in Protocol 3, by a description of the reconstruction of an atomic model of a structure from its rigid-body parameters. The most recent version of 3DNA, version 2.1, has new features for the analysis and manipulation of ensembles of structures, such as those deduced from nuclear magnetic resonance (NMR) measurements and molecular dynamic (MD) simulations; these features are presented in Protocols 4 and 5. In addition to the 3DNA stand-alone software package, the w3DNA web server, located at <a href="http://w3dna.rutgers.edu" target="_blank">http://w3dna.rutgers.edu</a>, provides a user-friendly interface to selected features of the software. Protocol 6 demonstrates a novel feature of the site for building models of long DNA molecules decorated with bound proteins at user-specified locations.

The 3DNA software package is a popular and versatile bioinformatics tool with capabilities to analyze, construct, and visualize three-dimensional nucleic acid structures. This article presents detailed protocols for a subset of new and popular features available in 3DNA, applicable to both individual structures and ensembles of related structures.

Análisis y construcción de estructuras de ácidos nucleicos con 3DNA

The 3DNA software package is a popular and versatile bioinformatics tool with capabilities to analyze, construct, and visualize three-dimensional nucleic ...

A Chemical Screening Procedure for Glucocorticoid Signaling with a Zebrafish Larva Luciferase Reporter System

Glucocorticoid stress hormones and their artificial derivatives are widely used drugs to treat inflammation, but long-term treatment with glucocorticoids can lead to severe side effects. Test systems are needed to search for novel compounds influencing glucocorticoid signaling in vivo or to determine unwanted effects of compounds on the glucocorticoid signaling pathway. We have established a transgenic zebrafish assay which allows the measurement of glucocorticoid signaling activity in vivo and in real-time, the GRIZLY assay (Glucocorticoid Responsive In vivo Zebrafish Luciferase activitY). The luciferase-based assay detects effects on glucocorticoid signaling with high sensitivity and specificity, including effects by compounds that require metabolization or affect endogenous glucocorticoid production. We present here a detailed protocol for conducting chemical screens with this assay. We describe data acquisition, normalization, and analysis, placing a focus on quality control and data visualization. The assay provides a simple, time-resolved, and quantitative readout. It can be operated as a stand-alone platform, but is also easily integrated into high-throughput screening workflows. It furthermore allows for many applications beyond chemical screening, such as environmental monitoring of endocrine disruptors or stress research.

We describe the procedure and data analysis of a chemical screening system for glucocorticoid stress hormone signaling using zebrafish larvae: the Glucocorticoid Responsive In vivo Zebrafish Luciferase activitY (GRIZLY) assay. The assay sensitively and specifically detects effects on glucocorticoid signaling by compounds that require metabolization or affect endogenous glucocorticoid production.

Un procedimiento de detección química de glucocorticoides Señalización con un sistema indicador de pez cebra Larva luciferasa

Glucocorticoid stress hormones and their artificial derivatives are widely used drugs to treat inflammation, but long-term treatment with glucocorticoids ...

Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues

S-Adenosyl-l-methionine (AdoMet or SAM)-dependent methyltransferases (MTase) catalyze the transfer of the activated methyl group from AdoMet to specific positions in DNA, RNA, proteins and small biomolecules. This natural methylation reaction can be expanded to a wide variety of alkylation reactions using synthetic cofactor analogues. Replacement of the reactive sulfonium center of AdoMet with an aziridine ring leads to cofactors which can be coupled with DNA by various DNA MTases. These aziridine cofactors can be equipped with reporter groups at different positions of the adenine moiety and used for Sequence-specific Methyltransferase-Induced Labeling of DNA (SMILing DNA). As a typical example we give a protocol for biotinylation of pBR322 plasmid DNA at the 5&#8217;-ATCGAT-3&#8217; sequence with the DNA MTase M.BseCI and the aziridine cofactor 6BAz in one step. Extension of the activated methyl group with unsaturated alkyl groups results in another class of AdoMet analogues which are used for methyltransferase-directed Transfer of Activated Groups (mTAG). Since the extended side chains are activated by the sulfonium center and the unsaturated bond, these cofactors are called double-activated AdoMet analogues. These analogues not only function as cofactors for DNA MTases, like the aziridine cofactors, but also for RNA, protein and small molecule MTases. They are typically used for enzymatic modification of MTase substrates with unique functional groups which are labeled with reporter groups in a second chemical step. This is exemplified in a protocol for fluorescence labeling of histone H3 protein. A small propargyl group is transferred from the cofactor analogue SeAdoYn to the protein by the histone H3 lysine 4 (H3K4) MTase Set7/9 followed by click labeling of the alkynylated histone H3 with TAMRA azide. MTase-mediated labeling with cofactor analogues is an enabling technology for many exciting applications including identification and functional study of MTase substrates as well as DNA genotyping and methylation detection.

DNA and proteins are sequence-specifically labeled with affinity or fluorescent reporter groups using DNA or protein methyltransferases and synthetic cofactor analogues. Depending on the cofactor specificity of the enzymes, aziridine or double activated cofactor analogues are employed for one- or two-step labeling.

Etiquetado específico de secuencia de ácidos nucleicos y proteínas con metiltransferasas y el cofactor Análogos

S-Adenosyl-l-methionine (AdoMet or SAM)-dependent methyltransferases (MTase) catalyze the transfer of the activated methyl group from AdoMet to specific ...