Editing Protein quaternary structure (section)

==Intragenic complementation==

When multiple copies of a polypeptide encoded by a [[gene]] form a quaternary complex, this protein structure is referred to as a multimer.<ref>{{cite journal | vauthors = Crick FH, Orgel LE | title = The theory of inter-allelic complementation | journal = Journal of Molecular Biology | volume = 8 | pages = 161–165 | date = January 1964 | pmid = 14149958 | doi = 10.1016/s0022-2836(64)80156-x }}</ref>  When a multimer is formed from polypeptides produced by two different [[mutant]] [[allele]]s of a particular gene, the mixed multimer may exhibit greater functional activity than the unmixed multimers formed by each of the mutants alone.  In such a case, the phenomenon is referred to as [[complementation (genetics)#Intragenic complementation|intragenic complementation]] (also called inter-allelic complementation).  Intragenic complementation appears to be common and has been studied in many different genes in a variety of organisms including the fungi ''[[Neurospora crassa]]'', ''[[Saccharomyces cerevisiae]]'' and ''[[Schizosaccharomyces pombe]]''; the bacterium ''[[Salmonella]] typhimurium''; the virus [[Escherichia virus T4|bacteriophage T4]],<ref>{{cite journal | vauthors = Bernstein H, Edgar RS, Denhardt GH | title = Intragenic complementation among temperature sensitive mutants of bacteriophage T4D | journal = Genetics | volume = 51 | issue = 6 | pages = 987–1002 | date = June 1965 | pmid = 14337770 | pmc = 1210828 | doi = 10.1093/genetics/51.6.987 }}</ref> an RNA virus,<ref>{{cite journal | vauthors = Smallwood S, Cevik B, Moyer SA | title = Intragenic complementation and oligomerization of the L subunit of the sendai virus RNA polymerase | journal = Virology | volume = 304 | issue = 2 | pages = 235–245 | date = December 2002 | pmid = 12504565 | doi = 10.1006/viro.2002.1720 | doi-access = free }}</ref> and humans.<ref>{{cite journal | vauthors = Rodríguez-Pombo P, Pérez-Cerdá C, Pérez B, Desviat LR, Sánchez-Pulido L, Ugarte M | title = Towards a model to explain the intragenic complementation in the heteromultimeric protein propionyl-CoA carboxylase | journal = Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease | volume = 1740 | issue = 3 | pages = 489–498 | date = June 2005 | pmid = 15949719 | doi = 10.1016/j.bbadis.2004.10.009 | doi-access = free }}</ref>  The intermolecular forces likely responsible for self-recognition and multimer formation were discussed by Jehle.<ref>{{cite journal | vauthors = Jehle H | title = Intermolecular forces and biological specificity | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 50 | issue = 3 | pages = 516–524 | date = September 1963 | pmid = 16578546 | pmc = 221211 | doi = 10.1073/pnas.50.3.516 | bibcode = 1963PNAS...50..516J | doi-access = free }}</ref>