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A Clostridium perfringens hem Gene Cluster Contains a cysG B Homologue That Is Involved in Cobalamin Biosynthesis
Author(s) -
Koyama Michio,
Katayama Seiichi,
Kaji Masato,
Taniguchi Yuki,
Matsushita Osamu,
Minami Junzaburo,
Morita Shushi,
Okabe Akinobu
Publication year - 1999
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1999.tb03355.x
Subject(s) - clostridium perfringens , cobalamin , biology , biosynthesis , gene cluster , clostridium , clostridiaceae , gene , microbiology and biotechnology , genetics , biochemistry , bacteria , toxin , vitamin b12
The hem gene cluster, which consists of hemA, cysG B , hemC, hemD, hemB , and hemL genes, and encodes enzymes involved in the biosynthetic pathway from glutamyl‐tRNA to uroporphyrinogen III, has been identified by the cloning and sequencing of two overlapping DNA fragments from Clostridium perfringens NCTC8237. The deduced amino acid sequence of the N‐terminal region of C. perfringens HemD is homologous to those reported for the C‐terminal region of Salmonella typhimurium CysG and Clostridium josui HemD. C, perfringens CysG B is a predicted 220‐residue protein which shows homology to the N‐terminal region of S. typhimurium CysG. Disruption of the cysG B gene in C. perfringens strain 13 by homologous recombination reduced cobalamin (vitamin B 12 ) levels by a factor of 200. When grown in vitamin B12‐deficient medium, the mutant strain showed a four‐fold increase in its doubling time compared with that of the wild‐type strain, and this effect was counteracted by supplementing the medium with vitamin B 12 . These results suggest that C. perfringens CysG B is involved in the chelation of cobalt to precorrin II as suggested for the CysG B domain of S. typhimurium CysG, enabling the synthesis of cobalamin.