Domain-swapping is a process in which two or more identical protein monomers exchange structural elements and fold into dimers or multimers. The individual units of such oligomers are structurally similar to the original monomer. In order for a protein to be considered domain-swapped the structures of both the monomer and the domain-swapped oligomer need to be present. If one of the structures is that of a homologous protein then the protein is said to be quasi-domain swapped. If only the domain-swapped structure is available then the protein is considered a candidate for domain-swapping. Several inter-protein interfaces are formed upon domain-swapping. The interface whose inter-protein interactions mimic those present in the monomer is called the primary interface. However, new interfaces which are not present in the monomer can also be formed and such interfaces are called secondary interfaces. Many proteins swap only a single secondary structural element and in such cases this “domain” can be thought of as being swapped. However, there are proteins where the size of the “swapped” region is similar to that of the other region. Here you have an example of a domain-swapped protein dimer. This is the structure of domain swapped dimer crystal structure of loop1 deletion mutant in Single-chain Monellin, from the plant Dioscoreophyllum cumminsii (PDB code: 5XFU)
#molecularart ... #immolecular ... #domain ... #swapping ... #dimer ... #monellin ... #xray
Structure of the domain-swapped protein rendered with @proteinimaging and depicted with @corelphotopaint
#molecularart ... #immolecular ... #domain ... #swapping ... #dimer ... #monellin ... #xray
Structure of the domain-swapped protein rendered with @proteinimaging and depicted with @corelphotopaint
