title: Structural analysis of a putative SAM-dependent methyltransferase, YtqB, from Bacillus subtilis.
abstract: S-adenosyl-L-methionine (SAM)-dependent methyltransferases (MTases) methylate diverse biological molecules using a SAM cofactor. The ytqB gene of Bacillus subtilis encodes a putative MTase and its biological function has never been characterized. To reveal the structural features and the cofactor binding mode of YtqB, we have determined the crystal structures of YtqB alone and in complex with its cofactor, SAM, at 1.9 Å and 2.2 Å resolutions, respectively. YtqB folds into a β-sheet sandwiched by two α-helical layers, and assembles into a dimeric form. Each YtqB monomer contains one SAM binding site, which shapes SAM into a slightly curved conformation and exposes the reactive methyl group of SAM potentially to a substrate. Our comparative structural analysis of YtqB and its homologues indicates that YtqB is a SAM-dependent class I MTase, and provides insights into the substrate binding site of YtqB.
authors.affiliation: Department of Systems Immunology, College of Biomedical Science, Kangwon National University, Chuncheon 200-701, Republic of Korea.
authors.forename: Sun Cheol
authors.initials: SC
authors.lastname: Park
authors.affiliation: Department of Systems Immunology, College of Biomedical Science, Kangwon National University, Chuncheon 200-701, Republic of Korea.
authors.forename: Wan Seok
authors.initials: WS
authors.lastname: Song
authors.affiliation: Department of Systems Immunology, College of Biomedical Science, Kangwon National University, Chuncheon 200-701, Republic of Korea; Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 200-701, Republic of Korea. Electronic address: sungil@kangwon.ac.kr.
authors.forename: Sung-il
authors.initials: SI
authors.lastname: Yoon
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D008780:Methyltransferases / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D055503:Protein Multimerization; D012436:S-Adenosylmethionine / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D012436:S-Adenosylmethionine; D008780:Methyltransferases
keywords: Bacillus subtilis; Crystal structure; Methyltransferase; S-adenosyl-l-methionine; YtqB