Protein–protein interaction

A protein-protein interaction is an interaction between two or more proteins. They are mainly based on non-covalent interactions, such as van der Waals forces and hydrogen bonds, electrostatic interactions and hydrophobic effects of amino acid residues near-surface protein domains between the proteins involved.

Properties

Protein -protein interactions play a key role in virtually all biological processes in which proteins are involved. These include, in particular, signal transduction, transport functions and the cytoskeleton. Therefore, protein -protein interactions are the subject of research for many areas of life sciences. All of the protein -protein interactions, which form a network of approximately 650,000 interact in the human body, is generally referred to as interactome and registered in databases such as KEGG and Reactome.

List of methods for the determination of protein -protein interactions

Protein -protein interactions can be examined in the course of a protein characterization experiments using biochemical and biophysical methods. These include, among others:

  • The yeast two -hybrid system and the bacterial two-hybrid system, two molecular-biological method using fusion proteins form a functional transcription factor in cells after interaction
  • The molecular display, such as phage display or yeast display, is a screening method wherein the proteins are expressed on the surface of bacteriophage and their encoding cDNA can be identified by interaction
  • Förster resonance energy transfer and bioluminescence resonance energy transfer, based on a physical phenomenon, show at the dye- conjugated proteins energy transfer in an interaction
  • Bimolecular fluorescence complementation that, a biochemical and biophysical methods, based on the merger of two previously separate fragments of green fluorescent protein for interaction with the conjugated proteins, analogous to the enzyme fragment complementation
  • Fluorescence correlation spectroscopy, fluorescence life time correlation spectroscopy
  • Surface plasmon resonance spectroscopy, a quantitative physical process based on a detection of the change of the layer thickness of the bound proteins by interaction
  • The bio -layer interferometry measures the interference in the addition of a modified protein on a layer of another protein
  • NMR spectroscopy, a method for determining the spatial structure of a protein
  • Ligand binding assay such as the radioligand binding, a quantitative biochemical method based on a radiation measurement of a mobile radio-labeled protein ligand for interaction with an immobilized protein
  • The alanine scan, several targeted mutagenesis to identify the amino acids necessary for binding
  • Cross-linking, a chemical method for the fixation of interacting proteins for subsequent analysis can be made using photo - reactive amino acid analogues are incorporated into the protein during expression and in vivo, usually combined with a Western Blot, or MALDI-TOF
  • Label transfer transmits a signal from one molecule to another bounding.
  • Affinity chromatography, a chromatographic separation method using a protein -conjugated stationary phase for the isolation of interacting proteins in the mobile phase
  • The affinity electrophoresis, affinity chromatography, a similar electrophoretic methods
  • Pull-down assays, such as co- immunoprecipitation or SPINE ( Strep- protein interaction experiment ), methods based on precipitation and subsequent analysis of protein complexes
  • Quantitative immunoprecipitation combined with knock-down ( QUICK)
  • Native gel electrophoresis show on interaction of proteins whose altered migration behavior in gel electrophoresis.
  • Far - Western blot used after incubation of a Western blot with the interaction partners this as a target for immunostaining
  • Proximity Ligation Assay
  • Protein - fragment complementation assay, similar to the bimolecular fluorescence complementation, but with two enzyme instead of two halves Fluorophorhälften.
  • Microscale thermophoresis
  • Isothermal Titration Calorimetry
  • By a density gradient centrifugation or a gel permeation chromatography of the modified hydrodynamic radius of a protein complex can be determined.

By comparing the amino acid sequence databases such as BLASTp and Pfam sequence-related proteins can give an indication of the possible functions of the protein to be tested with known functions. Furthermore, using theoretical, computer-based method as part of a protein structure prediction, the prediction of protein -protein interactions partially possible.

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