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PMID: 9324256 Published · ppublish English Journal Article Research Support, U.S. Gov't, P.H.S.

Repression of the cob operon of Salmonella typhimurium by adenosylcobalamin is influenced by mutations in the pdu operon.

Journal of bacteriology ·Vol. 179 ·No. 19 ·1997-10-00 ·Pages 6084-91

Ailion M, Roth JR

Abstract

The cob operon encodes functions needed for the biosynthesis of adenosylcobalamin (Ado-B12). Propanediol induces transcription of the cob operon and the neighboring pdu operon, which encodes proteins for the B12-dependent degradation of propanediol. Expression of the cob (but not the pdu) operon is repressed by exogenous cyanocobalamin. Evidence is provided that cob operon repression is signaled by internally generated Ado-B12, which can be formed either by the CobA adenosyltransferase or by an alternative adenosyltransferase (AdoT) that we infer is encoded within the pdu operon. Repression is also affected by mutations (AdoB) in the pdu operon that map upstream of the inferred pdu adenosyltransferase gene. Such mutations allow cobalamin to mediate repression at concentrations 100-fold lower than those needed in the wild type. It is proposed that these mutations eliminate a component of the propanediol dehydratase enzyme complex (PduCDE) and that this complex competes with the cob regulatory mechanism for a limited supply of Ado-B12.

MeSH Terms
Alkyl and Aryl Transferases Bacterial Proteins Cobamides/biosynthesis,genetics,pharmacology Gene Deletion Gene Expression Regulation, Bacterial Mutagenesis, Insertional Mutation Operon Promoter Regions, Genetic Propylene Glycols/metabolism,pharmacology Salmonella typhimurium/genetics,metabolism Transferases/genetics Vitamin B 12/metabolism,pharmacology
Chemicals
Bacterial Proteins Cobamides Propylene Glycols Transferases Alkyl and Aryl Transferases ATP-corrinoid adenosyltransferase cobamamide Vitamin B 12
Authors & Affiliations
2 authors, click to expand affiliations / ORCID
Ailion M
Department of Biology, University of Utah, Salt Lake City, 84112, USA.
Roth J R
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Article Info
Journal
Journal of bacteriology
Abbr.
J Bacteriol
ISSN
0021-9193
DOI
10.1128/jb.179.19.6084-6091.1997
Published
1997-10-00
Pages
6084-91
Language
English
Region
United States
NLM ID
2985120R
PMCID
PMC179512
Subset
IM
Grants
NIGMS NIH HHS · GM34804 · United States
External Links
PubMed source DOI: 10.1128/jb.179.19.6084-6091.1997 PMC Full Text View journal details
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