Affiliation:
1. Center for Biological Resource Recovery and Department of Biochemistry and Molecular Biology,1 and
2. Department of Chemistry and Center for Metalloenzyme Studies,2 University of Georgia, Athens, Georgia 30602
Abstract
ABSTRACT
A five-gene cluster encoding four nonheme iron proteins and a flavoprotein from the thermophilic anaerobic bacterium
Clostridium thermoaceticum
(
Moorella thermoacetica
) was cloned and sequenced. Based on analysis of deduced amino acid sequences, the genes were identified as
rub
(rubredoxin),
rbo
(rubredoxin oxidoreductase),
rbr
(rubrerythrin),
fprA
(type A flavoprotein), and a gene referred to as
hrb
(high-molecular-weight rubredoxin). Northern blot analysis demonstrated that the five-gene cluster is organized as two subclusters, consisting of two divergently transcribed operons,
rbr-fprA-hrb
and
rbo-rub
. The
rbr, fprA
, and
rub
genes were expressed in
Escherichia coli
, and their encoded recombinant proteins were purified. The molecular masses, UV-visible absorption spectra, and cofactor contents of the recombinant rubrerythrin, rubredoxin, and type A flavoprotein were similar to those of respective homologs from other microorganisms. Antibodies raised against
Desulfovibrio vulgaris
Rbr reacted with both native and recombinant Rbr from
C. thermoaceticum
, indicating that this protein was expressed in the native organism. Since Rbr and Rbo have been recently implicated in oxidative stress protection in several anaerobic bacteria and archaea, we suggest a similar function of these proteins in oxygen tolerance of
C. thermoaceticum
.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
73 articles.
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