The zinc finger protein Ynr046w is plurifunctional and a component of the eRF1 methyltransferase in yeast.
Protein release factor eRF1 in Saccharomyces cerevisiae, in complex with eRF3 and GTP, is methylated on a functionally crucial Gln residue by the S-adenosylmethionine-dependent methyltransferase Ydr140w. Here we show that eRF1 methylation, in addition to these previously characterized components, requires a 15-kDa zinc-binding protein, Ynr046w. Co-expression in Escherichia coli of Ynr046w and Ydr140w allows the latter to be recovered in soluble form rather than as inclusion bodies, and the two proteins co-purify on nickel-nitrilotriacetic acid chromatography when Ydr140w alone carries a His tag. The crystal structure of Ynr046w has been determined to 1.7 A resolution. It comprises a zinc-binding domain built from both the N- and C-terminal sequences and an inserted domain, absent from bacterial and archaeal orthologs of the protein, composed of three alpha-helices. The active methyltransferase is the heterodimer Ydr140w.Ynr046w, but when alone, both in solution and in crystals, Ynr046w appears to be a homodimer. The Ynr046w eRF1 methyltransferase subunit is shared by the tRNA methyltransferase Trm11p and probably by two other enzymes containing a Rossman fold.
Heurgué-Hamard
Valérie
V
UPR 9073 du CNRS, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
Graille
Marc
M
Scrima
Nathalie
N
Ulryck
Nathalie
N
Champ
Stéphanie
S
van Tilbeurgh
Herman
H
Buckingham
Richard H
RH
D000595:Amino Acid Sequence; D000818:Animals; D004926:Escherichia coli / Q000378:metabolism; D005973:Glutamine / Q000737:chemistry; D006801:Humans; D008780:Methyltransferases / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D009532:Nickel / Q000737:chemistry; D010454:Peptide Termination Factors / Q000737:chemistry / Q000502:physiology*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D015032:Zinc / Q000737:chemistry; D016335:Zinc Fingers; D012359:tRNA Methyltransferases
D010454:Peptide Termination Factors; C080775:SUP45 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D005973:Glutamine; D009532:Nickel; D008780:Methyltransferases; D012359:tRNA Methyltransferases; C502204:Trm11 protein, S cerevisiae; C502205:Trm112 protein, S cerevisiae; D015032:Zinc