title: Two related superfamilies of putative helicases involved in replication, recombination, repair and expression of DNA and RNA genomes.
abstract: In the course of systematic analysis of protein sequences containing the purine NTP-binding motif, a new superfamily was delineated which included 25 established or putative helicases of Escherichia coli, yeast, insects, mammals, pox- and herpesviruses, a yeast mitochondrial plasmid and three groups of positive strand RNA viruses. These proteins contained 7 distinct highly conserved segments two of which corresponded to the "A" and "B" sites of the NTP-binding motif. Typical of the new superfamily was an abridged consensus for the "A" site, GxGKS/T, instead of the classical G/AxxxxGKS/T. Secondary structure predictions indicated that each of the conserved segments might constitute a separate structural unit centering at a beta-turn. All previously characterized mutations impairing the function of the yeast helicase RAD3 in DNA repair mapped to one of the conserved segments. A degree of similarity was revealed between the consensus pattern of conserved amino acid residues derived for the new superfamily and that of another recently described protein superfamily including a different set of prokaryotic, eukaryotic and viral (putative) helicases.
authors.affiliation: Institute of Poliomyelitis and Viral Encephalitides, USSR Academy of Medical Sciences, Moscow.
authors.forename: A E
authors.initials: AE
authors.lastname: Gorbalenya
authors.forename: E V
authors.initials: EV
authors.lastname: Koonin
authors.forename: A P
authors.initials: AP
authors.lastname: Donchenko
authors.forename: V M
authors.initials: VM
authors.lastname: Blinov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D004265:DNA Helicases / Q000235:genetics* / Q000502:physiology; D004260:DNA Repair; D004261:DNA Replication; D004279:DNA, Viral / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D043583:Nucleoside-Triphosphatase; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics*; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004279:DNA, Viral; D005656:Fungal Proteins; D012367:RNA, Viral; D014764:Viral Proteins; D010744:Phosphoric Monoester Hydrolases; D043583:Nucleoside-Triphosphatase; D004265:DNA Helicases