title: A metal-binding motif implicated in RNA recognition by an aminoacyl-tRNA synthetase and by a retroviral gene product.
abstract: A randomly generated mutation in Escherichia coli alanine tRNA synthetase compensates for a mutation in its cognate tRNA. The enzyme's mutation occurs next to a Cys-X2-Cys-X6-His-X2-His metal-binding motif that is distinct from the zinc finger motif found in some DNA-binding proteins. Instead, the synthetase's metal binding domain resembles the Cys-X2-Cys-X4-His-X4-Cys metal-binding domain of the gag gene product of retroviruses. For Ala-tRNA synthetase, the metal bound at the Cys-His motif is important specifically for the tRNA-dependent step of catalysis, and the enzyme-tRNA interaction is dependent on the geometry of metal co-ordination to the enzyme. These data, and the demonstrated sensitivity of RNA packaging to mutations in the metal-binding domain of the gag gene product of retroviruses, suggest that an aminoacyl-tRNA synthetase and retroviruses have adopted a related metal-binding motif for RNA recognition.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: W T
authors.initials: WT
authors.lastname: Miller
authors.forename: P
authors.initials: P
authors.lastname: Schimmel
mesh_terms: D000412:Alanine-tRNA Ligase / Q000235:genetics* / Q000378:metabolism; D000494:Allosteric Regulation; D000495:Allosteric Site; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003035:Cobalt / Q000378:metabolism; D016384:Consensus Sequence; D004926:Escherichia coli / Q000235:genetics*; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D015750:Genes, gag; D008969:Molecular Sequence Data; D009154:Mutation; D012329:RNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D012344:RNA, Transfer, Ala / Q000235:genetics* / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics*; D015032:Zinc / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D015683:Gene Products, gag; D012329:RNA, Bacterial; D012344:RNA, Transfer, Ala; D003035:Cobalt; D000412:Alanine-tRNA Ligase; D015032:Zinc