Protein–protein interactions (PPIs) are physical contacts of high specificity established between two or more protein molecules as a result of biochemical events steered by interactions that include electrostatic forces, hydrogen bonding and the hydrophobic effect. Many are physical contacts with molecular associations between chains that occur in a cell or in a living organism in a specific biomolecular context. To describe the types of protein–protein interactions (PPIs) it is important to consider that proteins can interact in a "transient" way (to produce some specific effect in a short time, like a signal transduction) or to interact with other proteins in a "stable" way to form complexes that become molecular machines within the living systems. A protein complex assembly can result in the formation of homo-oligomeric or hetero-oligomeric complexes. In addition to the conventional complexes, as enzyme-inhibitor and antibody-antigen, interactions can also be established between domain-domain and domain-peptide. Another important distinction to identify protein-protein interactions is the way they have been determined, since there are techniques that measure direct physical interactions between protein pairs, named “binary” methods, while there are other techniques that measure physical interactions among groups of proteins, without pairwise determination of protein partners, named “co-complex” methods. In the stabilization of protein-protein complexes, the role of hydrophobic interactions is often very relevant. For instance, you can see in this enzyme, the human Inosine-5'-monophosphate dehydrogenase, how the monomers are bond by hydrophobic interactions (see several aromatic residues in the cleft between subunits) (PBD code: 7RFF).
#molecularart ... #immolecular ... #monomer ... #oligomer ... #stabilization ... #hydrophobicinteractions ... #aromaticresidues ... #PPi
Structure of Inosine-5'-monophosphate dehydrogenase rendered with @proteinimaging and depicted with @corelphotopaint
#molecularart ... #immolecular ... #monomer ... #oligomer ... #stabilization ... #hydrophobicinteractions ... #aromaticresidues ... #PPi
Structure of Inosine-5'-monophosphate dehydrogenase rendered with @proteinimaging and depicted with @corelphotopaint
