Disulfide-linked Protein Complexes
Disulfide-linked Protein Complexes - Related Videos
02:44
Non-Reducing SDS PAGE: A Method to Analyze Disulfide-Linked Multimeric Protein Complexes
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2025
This video describes the technique of separating the protein samples by non-reducing SDS-PAGE to analyze the multimeric protein complexes. This technique retains the multimer subunits of a protein held by the disulfide bonds which can later be analyzed by western blotting.
12:05
Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
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Cited by 7 •
2013
Biophysical and biochemical studies of interactions among membrane-embedded protein domains face many technical challenges, the first of which is obtaining appropriate study material. This article describes a protocol for producing and purifying disulfide-stabilized transmembrane peptide complexes that are suitable for structural analysis by solution nuclear magnetic resonance (NMR) and other analytical applications.
02:04
Covalently Linked Protein Regulators
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2020
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified. These groups modify specific amino acids in a protein.
01:57
Protein Complexes with Interchangeable Parts
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2020
Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct. The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
03:51
Fluorescent Functionalization of Virus-Like Particles via Disulfide Re-bridging
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2026
Source: Chen, Z., et al. Making Conjugation-induced Fluorescent PEGylated Virus-like Particles by Dibromomaleimide-disulfide Chemistry. J. Vis. Exp. (2018)This video demonstrates the fluorescent functionalization of virus-like particles by re-bridging reduced disulfides with a polyethylene glycol (PEG) linker, producing stable, trackable conjugates suitable for cellular imaging and targeted delivery in biomedical applications.
FAQs
Oxidation converts paired cysteine thiol groups into disulfide bonds, allowing separate protein chains to remain connected as an assembly. Reducing conditions reverse this chemistry by restoring the thiol groups, which can release the linked chains. This reversible behavior makes redox conditions central to studying complex stability and regulation, particularly when comparing protein states in biochemical experiments.
Cysteine residues provide the reactive thiol groups needed to form the covalent links between protein chains. Their participation can reinforce structural stability while also influencing biological function through changes in assembly state. Examining cysteine-dependent linkage therefore helps connect protein structure with folding behavior, extracellular persistence, and regulation by the surrounding redox environment.
Researchers compare protein behavior under nonreducing and reducing conditions. A complex detected without reducing treatment but disrupted after reduction is consistent with disulfide-dependent linkage, whereas a noncovalent interaction does not rely on those covalent bonds. This comparison helps separate chemically linked assemblies from complexes maintained through other forms of association.
A practical workflow analyzes the protein sample by electrophoresis under nonreducing conditions and then compares it with a reducing condition that can break disulfide bonds. Differences between the two analyses reveal whether linked chains are present and whether the assembly depends on disulfide chemistry. This paired design provides a direct biochemical test of covalent complex formation.
Mutational analysis tests whether changing particular cysteine residues alters formation of the protein assembly. If a mutation affects the linked complex, that residue may contribute to the disulfide connection or to the structural context that supports it. Used alongside electrophoresis and biochemical purification, this approach helps assign cysteine-dependent features to specific protein components.
Biochemical purification can isolate the relevant protein assembly for examination, while redox comparisons test whether its integrity depends on disulfide bonds. Together, these approaches support studies of protein folding, extracellular stability, and redox regulation. They can also help investigate disease-associated changes in protein structure by revealing altered formation or disruption of covalent assemblies.