TY - JOUR
T1 - CbiZ, an amidohydrolase enzyme required for salvaging the coenzyme B 12 precursor cobinamide in archaea
AU - Woodson, Jesse D.
AU - Escalante-Semerena, Jorge C.
PY - 2004/3/9
Y1 - 2004/3/9
N2 - The existence of a pathway for salvaging the coenzyme B12 precursor dicyanocobinamide (Cbi) from the environment was established by genetic and biochemical means. The pathway requires the function of a previously unidentified amidohydrolase enzyme that converts adenosylcobinamide to adenosylcobyric acid, a bona fide intermediate of the de novo coenzyme B 12 biosynthetic route. The cbiZ gene of the methanogenic archaeon Methanosarcina mazei strain Göl was cloned, was overproduced in Escherichia coli, and the recombinant protein was isolated to homogeneity. HPLC, UV-visible spectroscopy, MS, and bioassay data established adenosylcobyric as the corrinoid product of the CbiZ-catalyzed reaction. Inactivation of the cbiZ gene in the extremely halophilic archaeon Halobacterium sp. strain NRC-1 blocked the ability of this archaeon to salvage Cbi. cbiZ function restored Cbi salvaging in a strain of the bacterium Salmonella enterica, whose Cbi-salvaging pathway was blocked. The salvaging of Cbi through the CbiZ enzyme appears to be an archaeal strategy because all of the genomes of B12-producing archaea have a cbiZ ortholog. Reasons for the evolution of two distinct pathways for Cbi salvaging in prokaryotes are discussed.
AB - The existence of a pathway for salvaging the coenzyme B12 precursor dicyanocobinamide (Cbi) from the environment was established by genetic and biochemical means. The pathway requires the function of a previously unidentified amidohydrolase enzyme that converts adenosylcobinamide to adenosylcobyric acid, a bona fide intermediate of the de novo coenzyme B 12 biosynthetic route. The cbiZ gene of the methanogenic archaeon Methanosarcina mazei strain Göl was cloned, was overproduced in Escherichia coli, and the recombinant protein was isolated to homogeneity. HPLC, UV-visible spectroscopy, MS, and bioassay data established adenosylcobyric as the corrinoid product of the CbiZ-catalyzed reaction. Inactivation of the cbiZ gene in the extremely halophilic archaeon Halobacterium sp. strain NRC-1 blocked the ability of this archaeon to salvage Cbi. cbiZ function restored Cbi salvaging in a strain of the bacterium Salmonella enterica, whose Cbi-salvaging pathway was blocked. The salvaging of Cbi through the CbiZ enzyme appears to be an archaeal strategy because all of the genomes of B12-producing archaea have a cbiZ ortholog. Reasons for the evolution of two distinct pathways for Cbi salvaging in prokaryotes are discussed.
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U2 - 10.1073/pnas.0305939101
DO - 10.1073/pnas.0305939101
M3 - Article
C2 - 14990804
AN - SCOPUS:1542723403
SN - 0027-8424
VL - 101
SP - 3591
EP - 3596
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 10
ER -