Methyladeninylcobamide functions as the cofactor of methionine synthase in a Cyanobacterium, Spirulina platensis NIES-39.
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.
Tanioka
Yuri
Y
Department of Nutrition, Junior College of Tokyo University of Agriculture, Tokyo, Japan. y3taniok@nodai.ac.jp
Miyamoto
Emi
E
Yabuta
Yukinori
Y
Ohnishi
Kouhei
K
Fujita
Tomoyuki
T
Yamaji
Ryoichi
R
Misono
Haruo
H
Shigeoka
Shigeru
S
Nakano
Yoshihisa
Y
Inui
Hiroshi
H
Watanabe
Fumio
F
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
D007287:Inorganic Chemicals; D009930:Organic Chemicals; D012436:S-Adenosylmethionine; C019476:mecobalamin; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D014805:Vitamin B 12