Multi-protein Complex Isolation
Multi-protein Complex Isolation - Related Videos
05:13
Isolation of Proteins from Viral DNA-protein Complexes
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2026
Source: Dembowski, J. A., et al. Purification of Viral DNA for the Identification of Associated Viral and Cellular Proteins. J. Vis. Exp. (2017).This video demonstrates the isolation of protein–viral DNA complexes from cell nuclei using click chemistry and magnetic bead purification. The protocol involves labeling viral genomes with alkyne-modified nucleotides, biotinylation via a click reaction, and binding to streptavidin-coated magnetic beads. Following washing and heat elution, the purified...
10:50
Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography
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Cited by 37 •
2010
The cell permeable crosslinker DSP [dithiobis-(succinimidyl propionate)] stabilizes transient and labile interactions in vivo, which allows their isolation using stringent protein complex purification techniques. Here we present a technique for crosslinking cells grown in culture followed by isolation of protein complexes by immunoprecipitation.
08:51
An in vivo Crosslinking Approach to Isolate Protein Complexes From Drosophila Embryos
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Cited by 6 •
2014
Multi-component protein complexes play crucial roles during cellular function and development. Here we describe a method used to isolate native protein complexes from Drosophila embryos after in vivo crosslinking followed by purification of the crosslinked complexes for subsequent structure-function analysis.
06:45
Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification (BiCAP)
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Cited by 4 •
2018
This manuscript describes the protocol for Bimolecular Complementation Affinity Purification (BiCAP). This novel method facilitates the specific isolation and downstream proteomic characterization of any two interacting proteins, while excluding un-complexed individual proteins as well as complexes formed with competing binding partners.
02:41
Protein Complex Assembly
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2020
Proteins can form homomeric complexes with another unit of the same protein or heteromeric complexes with different types. Most protein complexes self-assemble spontaneously via ordered pathways, while some proteins need assembly factors that guide their proper assembly. Despite the crowded intracellular environment, proteins usually interact with their correct partners and form functional complexes. Many viruses self-assemble into a fully functional unit using the infected host cell to...
FAQs
These variables help determine whether noncovalent interactions remain stable during purification. Controlled pH and ionic strength can support the contacts between subunits, while temperature and protein concentration also influence complex stability. If conditions disrupt those interactions, the assembly may separate into free proteins, reducing the reliability of measurements such as stoichiometry, binding behavior, or enzymatic function.
Native composition allows the isolated assembly to reflect the interacting proteins as they occur together rather than as separated subunits or altered mixtures. Maintaining that composition is important when examining binding behavior, stoichiometry, structure, or activity. In chemistry and biochemistry, this connection helps relate molecular interactions to cellular processes and evaluate the functional properties of the assembly.
The three approaches distinguish complexes from free subunits and contaminants through different separation principles. Affinity chromatography uses selective interactions, size-exclusion chromatography separates according to molecular size, and density-based separation distinguishes materials by density. Their complementary roles allow researchers to select a separation strategy suited to the properties of the assembly and the quality of purification required.
A typical workflow begins by stabilizing the interacting proteins under controlled pH, ionic strength, temperature, and concentration. Researchers then apply a separation method such as affinity chromatography, size-exclusion chromatography, or density-based separation to distinguish the complex from free subunits and contaminants. The resulting preparation can support measurements of composition, binding, structure, and activity.
Commonly described options include affinity chromatography, size-exclusion chromatography, and density-based separation. Researchers can use these methods to separate the desired assembly from unbound material, free protein subunits, and other contaminants. Selecting among them depends on which distinguishing property is most useful, including selective interaction, molecular size, or density, while preserving the complex under controlled conditions.
Isolated assemblies enable measurements of stoichiometry, binding behavior, structure, and enzymatic function. These outcomes reveal how proteins associate and how their combined organization relates to activity. Such information helps connect molecular interactions with cellular processes and provides a basis for developing analytical methods, studying inhibitors, and designing engineered protein assemblies.
Purified complexes provide a controlled system for examining how molecular interactions influence structure and function. Measurements of binding behavior and enzymatic activity can support inhibitor studies, while information about composition and organization can guide engineered assemblies. This makes the isolation process relevant not only to characterization, but also to developing analytical approaches and manipulating protein interactions.