Guidelines for computer based structural and functional characterization of protein using the I-TASSER pipeline is described. Starting from query protein sequence, 3D models are generated using multiple threading alignments and iterative structural assembly simulations. Functional inferences are thereafter drawn based on matches to proteins with known structure and functions.
Rapid Synthesis and Screening of Chemically Activated Transcription Factors with GFP-based Reporters
1The Lewis-Sigler Institute for Integrative Genomics, Princeton University, 2Department of Molecular Biology, Princeton University, 3Division of Chemistry and Chemical Engineering, California Institute of Technology
This protocol describes an experimental procedure for the rapid construction of artificial transcription factors (ATFs) with cognate GFP reporters and quantification of the ATFs ability to stimulate GFP expression via flow cytometry.
1Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven and Leuven Institute for Neuroscience and Disease (LIND)
Leucine rich repeat kinases 1 and 2 (LRRK1 and LRRK2) are multidomain proteins which encode both GTPase and kinase domains and which are phosphorylated in cells. Here, we present a protocol to label LRRK1 and LRRK2 in cells with 32P orthophosphate, thereby providing a means to measure their overall cellular phophorylation levels.
Published September 18, 2013. Keywords: Cellular Biology, biology (general), biochemistry, bioengineering (general), LRRK1, LRRK2, metabolic labeling, 32P orthophosphate, immunoprecipitation, autoradiography
Chemically-blocked Antibody Microarray for Multiplexed High-throughput Profiling of Specific Protein Glycosylation in Complex Samples
1Institute for Hepatitis and Virus Research, 2Department of Microbiology and Immunology, Thomas Jefferson University, 3Drexel University College of Medicine, 4Van Andel Research Institute, 5Institute for Hepatitis and Virus Research, Serome Biosciences Inc.
In this study, we describe an improved protocol for a multiplexed high-throughput antibody microarray with lectin detection method that can be used in glycosylation profiling of specific proteins. This protocol features new reliable reagents and significantly reduces the time, cost, and lab equipment requirements as compared to the previous procedure.
Published May 4, 2012. Keywords: Molecular Biology, Glycoproteins, glycan-binding protein, specific protein glycosylation, multiplexed high-throughput glycan blocked antibody microarray
1Department of Microbiology, Biochemistry, & Immunology, Morehouse School of Medicine, 2Institute for Systems Biology, 3Advanced Medical & Dental Institute, Universiti Sains Malaysia
Techniques to dissect the mechanisms underlying the secretion of HIV-1 Nef in exosomes are described. Specific short peptides derived from Nef and protein transfection were exploited to determine the structure, function, and binding partners of Nef’s Secretion Modification Region. These procedures have general relevance in many mechanistic studies.
Published June 30, 2013. Keywords: Virology, Biochemistry, Immunology, Infection, Infectious Diseases, Molecular Biology, Medicine, Genetics, Microbiology, Genomics, Proteins, Exosomes, HIV, Peptides, Exocytosis, protein trafficking, secretion, HIV-1, Nef, Secretion Modification Region, SMR, peptide, AIDS, assay
Calmodulin (CaM) pull-down assay is an effective way to investigate the interaction of CaM with various proteins. This method uses CaM-sepharose beads for efficient and specific analysis of CaM-binding proteins. This provides an important tool to explore CaM signaling in cellular function.
1School of Life Sciences, University of Warwick, 2The Sainsbury Laboratory, Norwich Research Park, 3Research School of Biology, The Australian National University
We describe here a protocol for the purification and characterization of plant protein complexes. We demonstrate that by immunoprecipitating a single protein within a complex, so we can identify its post-translational modifications and its interacting partners.
1Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas
Procedures for complete reconstitution of a prototype voltage-gated potassium channel into lipid membranes are described. The reconstituted channels are suitable for biochemical assays, electrical recordings, ligand screening and electron crystallographic studies. These methods may have general applications to the structural and functional studies of other membrane proteins.
Published July 13, 2013. Keywords: Molecular Biology, Biochemistry, Genetics, Cellular Biology, Structural Biology, Biophysics, Membrane Lipids, Phospholipids, Carrier Proteins, Membrane Proteins, Micelles, Molecular Motor Proteins, life sciences, biochemistry, Amino Acids, Peptides, and Proteins, lipid-protein interaction, channel reconstitution, lipid-dependent gating, voltage-gated ion channel, conformation-specific ligands, lipids
1Genetics and Biochemistry Branch of the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
This article illustrates the use of pulse-chase radio labeling in combination with site-specific photocrosslinking to monitor interactions between a protein of interest and other factors in E. coli. Unlike traditional chemical cross-linking methods, this approach generates high resolution “snapshots” of an ordered assembly pathway in a living cell.
Investigating Receptor-ligand Systems of the Cellulosome with AFM-based Single-molecule Force Spectroscopy
1Lehrstuhl für Angewandte Physik and Center for Nanoscience, Ludwig-Maximilians-Universität
Cellulosomes are multienzyme complexes designed for digesting cellulose. AFM-based SMFS was used to study the mechanical properties and folding configuration of cellulosome-associated protein assemblies. We present a complete workflow for protein immobilization, data acquisition, and data analysis to study the interactions of individual receptor-ligand complexes involved in cellulosome assembly.