The human 2',5'-oligoadenylate synthetase family: interferon-induced proteins with unique enzymatic properties.
2',5'-Oligoadenylate synthetase (2',5'-OAS) was discovered and characterized as an interferon (IFN)-induced enzyme that in the presence of double-stranded (ds) RNA converts ATP into 2',5'-linked oligomers of adenosine with the general formula pppA(2'p'A)n, n > or = 1. The product is pppG2'p5'G when GTP is used as a substrate. Now, 20 years later, this activity is attributed to several well-characterized, homologous, and IFN-induced proteins in human cells. Three distinct forms of 2',5'-OAS exist, small, medium, and large, which contain 1, 2, and 3 OAS units, respectively, and are encoded by distinct genes clustered on the 2',5'-OAS locus on human chromosome 12. Recently, other IFN-induced proteins homologous to the OAS unit but devoid of the typical 2',5'-OAS catalytic activity have been described. These OAS-related proteins are encoded by a gene located at the proximity of the 2',5'-OAS locus. These findings illustrate the apparent structural and functional complexity of the human 2',5'-OAS family.
Rebouillat
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Institut Pasteur, Unité de Virologie et Immunologie Cellulaire, URA CNRS 1930, Paris, France.
Hovanessian
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AG
D015088:2',5'-Oligoadenylate Synthetase / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D004790:Enzyme Induction; D006801:Humans; D007372:Interferons / Q000494:pharmacology*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D012330:RNA, Double-Stranded / Q000235:genetics*
D007527:Isoenzymes; D012330:RNA, Double-Stranded; D007372:Interferons; D015088:2',5'-Oligoadenylate Synthetase