Protein Complex Separation
Protein Complex Separation - Related Videos
06:59
Multimer-PAGE for Separating Native Protein Complexes: A Hybrid Separation Technique Consisting of Blue Native-PAGE and SDS-PAGE to Separate Intact Multimeric Proteins From Tissue Lysate
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2025
This video describes multimeric PAGE for separating native protein complexes from tissue homogenates. The technique is a hybrid of blue native-PAGE and SDS-PAGE techniques. The separated complexes can be characterized and studied for their role in cell functioning.
07:29
Separating Protein with SDS-PAGE
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2023
Sodium Dodecyl Sulfate Poly-Acrylamide Gel Electrophoresis, or SDS-PAGE, is a widely-used technique for separating mixtures of proteins based on their size and nothing else. SDS, an anionic detergent, is used to produce an even charge across the length of proteins that have been linearized. By first loading them into a gel made of polyacrylamide and then applying an electric field to the gel, SDS-coated proteins are then separated. The electric field acts as the driving force, drawing the SDS...
08:17
Electrophoretic Separation of Proteins
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Cited by 29 •
2008
In this video, we demonstrate a method for electrophoretic separation of proteins using poly-acrylimide gel electrophoresis (PAGE).
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...
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...
FAQs
The choice depends on which physical or chemical property most clearly distinguishes the complex from other sample components. Size-exclusion chromatography separates according to size, ion-exchange chromatography according to charge, centrifugation according to density, and affinity purification according to binding affinity. Matching the method to the relevant property helps enrich the target assembly while reducing unrelated proteins.
These properties determine how protein assemblies behave during a particular separation process. Size influences movement through a chromatography medium, density affects sedimentation during centrifugation, charge governs interactions in ion-exchange chromatography, and binding affinity enables selective capture of molecules with compatible partners. Consequently, each method partitions the sample in a different way and can provide complementary information.
The separated material can be examined for complex stability and subunit composition after isolation. Analytical methods such as electrophoresis or mass spectrometry help determine which proteins are present and whether expected components occur together. Comparing these results with the separated fractions allows researchers to evaluate the composition of an assembly and identify associated interaction partners.
A general workflow begins with a cell, tissue, or purified sample and applies a separation method selected for the complex’s distinguishing property. Fractions or enriched material are then collected and analyzed using electrophoresis or mass spectrometry. This sequence connects physical partitioning with molecular characterization, allowing researchers to assess composition, stability, and associated proteins.
Electrophoresis and mass spectrometry provide complementary ways to examine separated material. Electrophoresis supports assessment of the proteins present in an isolated fraction, while mass spectrometry can help characterize subunit composition and interaction partners. Together, these analyses transform separated samples into evidence about the molecular makeup and associations of a protein assembly.
The approach is useful when researchers need to investigate cellular pathways, molecular machines, disease mechanisms, or potential therapeutic targets. Isolating complexes makes it possible to examine their subunits and interaction partners rather than studying only individual proteins. These findings can connect the composition of an assembly with its function or with changes associated with disease-related biology.