title: Two distinct roles for two functional cobaltochelatases (CbiK) in Desulfovibrio vulgaris hildenborough.
abstract: The sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough possesses a large number of porphyrin-containing proteins whose biosynthesis is poorly characterized. In this work, we have studied two putative CbiK cobaltochelatases present in the genome of D. vulgaris. The assays revealed that both enzymes insert cobalt and iron into sirohydrochlorin, with specific activities with iron lower than that measured with cobalt. Nevertheless, the two D. vulgaris chelatases complement an E. coli cysG mutant strain showing that, in vivo, they are able to load iron into sirohydrochlorin. The results showed that the functional cobaltochelatases have distinct roles with one, CbiK(C), likely to be the enzyme associated with cytoplasmic cobalamin biosynthesis, while the other, CbiK(P), is periplasmic located and possibly associated with an iron transport system. Finally, the ability of D. vulgaris to produce vitamin B 12 was also demonstrated in this work.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da Republica (EAN), 2780-157 Oeiras, Portugal.
authors.forename: Susana A L
authors.initials: SA
authors.lastname: Lobo
authors.forename: Amanda A
authors.initials: AA
authors.lastname: Brindley
authors.forename: Célia V
authors.initials: CV
authors.lastname: Romão
authors.forename: Helen K
authors.initials: HK
authors.lastname: Leech
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Warren
authors.forename: Lígia M
authors.initials: LM
authors.lastname: Saraiva
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001692:Biological Transport; D003593:Cytoplasm / Q000378:metabolism; D016969:Desulfovibrio vulgaris / Q000201:enzymology*; D004926:Escherichia coli / Q000378:metabolism; D016680:Genome, Bacterial; D007501:Iron / Q000378:metabolism; D008190:Lyases / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009154:Mutation; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014578:Uroporphyrins / Q000737:chemistry; D014805:Vitamin B 12 / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D014578:Uroporphyrins; C014188:sirohydrochlorin; D007501:Iron; D008190:Lyases; C033211:cobaltochelatase; D014805:Vitamin B 12