title: Bacterial Hen1 is a 3' terminal RNA ribose 2'-O-methyltransferase component of a bacterial RNA repair cassette.
abstract: Hen1 is an RNA ribose 2'-O-methyltransferase that modifies the 3' terminal nucleoside of eukaryal small regulatory RNAs. Here, we report that Hen1 homologs are present in bacterial proteomes from eight different phyla. Bacterial Hen1 is encoded by the proximal ORF of a two-gene operon that also encodes polynucleotide kinase-phosphatase (Pnkp), an RNA repair enzyme. Purified recombinant Clostridium thermocellum Hen1 is a homodimer of a 465-amino acid polypeptide. CthHen1 catalyzes methyl transfer from AdoMet to the 3' terminal nucleoside of an RNA oligonucleotide, but is unreactive with a synonymous DNA oligonucleotide or an RNA with a single 3'-terminal deoxyribose sugar. CthHen1 is optimally active at alkaline pH and dependent on manganese. Activity is inhibited by AdoHcy and abolished by mutations D291A and D316A in the putative AdoMet-binding pocket. The C-terminal fragment, Hen1-(259-465), comprises an autonomous monomeric methyltransferase domain.
authors.affiliation: Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Jain
authors.forename: Stewart
authors.initials: S
authors.lastname: Shuman
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D048013:Acetivibrio thermocellus / Q000235:genetics / Q000378:metabolism; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D011994:Recombinant Proteins; D012436:S-Adenosylmethionine; D008780:Methyltransferases; C052744:RNA 2'-O-methyltransferase