title: Methyladeninylcobamide functions as the cofactor of methionine synthase in a Cyanobacterium, Spirulina platensis NIES-39.
abstract: To clarify the physiological function of pseudovitamin B(12) (or adeninylcobamide; AdeCba) in Spirulina platensis NIES-39, cobalamin-dependent methionine synthase (MS) was characterized. We cloned the full-length Spirulina MS. The clone contained an open reading frame encoding a protein of 1183 amino acids with a molecular mass of 132 kDa. Deduced amino acid sequences of the Spirulina MS contained critical residues identical to cobalamin-, zinc-, S-adenosylmethionine-, and homocysteine-binding motifs. The recombinant Spirulina enzyme showed higher affinity for methyladeninylcobamide than methylcobalamin as a cofactor. These results indicate that Spirulina cells can utilize AdeCba synthesized as the cofactor for MS.
authors.affiliation: Department of Nutrition, Junior College of Tokyo University of Agriculture, Tokyo, Japan. y3taniok@nodai.ac.jp
authors.forename: Yuri
authors.initials: Y
authors.lastname: Tanioka
authors.forename: Emi
authors.initials: E
authors.lastname: Miyamoto
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Yabuta
authors.forename: Kouhei
authors.initials: K
authors.lastname: Ohnishi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Fujita
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Yamaji
authors.forename: Haruo
authors.initials: H
authors.lastname: Misono
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Nakano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inui
authors.forename: Fumio
authors.initials: F
authors.lastname: Watanabe
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism*; D007287:Inorganic Chemicals; D008969:Molecular Sequence Data; D009930:Organic Chemicals; D017434:Protein Structure, Tertiary / Q000235:genetics; D012436:S-Adenosylmethionine / Q000235:genetics / Q000378:metabolism; D014805:Vitamin B 12 / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism
chemical_list: D007287:Inorganic Chemicals; D009930:Organic Chemicals; D012436:S-Adenosylmethionine; C019476:mecobalamin; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D014805:Vitamin B 12