A single regulatory gene integrates control of vitamin B12 synthesis and propanediol degradation

Abstract

The cob operon of Salmonella typhimurium encodes enzymes required for synthesis of adenosyl-cobalamin (vitamin B12). The pdu operon encodes enzymes needed for use of propanediol as a carbon source, including an adenosyl-cobalamin-dependent enzyme, propanediol dehydratase. These two operons both map near min 41 of the S. typhimurium linkage map and are transcribed divergently. Here we report that the cob and pdu operons form a single regulon. Transcription of this regulon is induced by either glycerol or propanediol.

Localization of Proteins to the 1,2-Propanediol Utilization Microcompartment by Non-native Signal Sequences Is Mediated by a Common Hydrophobic Motif

“…S. enterica LT2, however, can express both Pdu and Eut MCPs, and we wished only to observe Pdu MCP formation and cargo encapsulation. The transcriptional regulator PocR is necessary for Pdu MCP formation (19,(21)(22)(23). We confirmed that the analogous transcriptional regulator EutR is necessary for Eut MCP formation by two methods: first using a fluorescent reporter of P eut transcription (24,25) and then using a fluorescent reporter of encapsulation in the Eut or Pdu MCP (8).…”

The complete coenzyme B12 biosynthesis gene cluster of Lactobacillus reuteri CRL1098

“…Its presence is in agreement with the experimental evidence gathered during this study suggesting co-regulation between the B 12 cluster and the pdu genes located immediately upstream. PocR has been shown to be an activator of the coenzyme B 12 biosynthesis cluster (Bobik et al, 1992), and is likely to be involved in the observed negative feedback phenomena. Furthermore, PocR itself has been shown to be activated under carbon and redox control (Ailion et al, 1993), which explains why we observed in all conditions assayed an induction of the B 12 biosynthesis cluster during the late-exponential in comparison to the mid-exponential phase.…”

“…The presence of a transposase immediately upstream of the first gene of the B 12 cluster might have disturbed the riboswitch. The regulatory gene pocR (Bobik et al, 1992), which is often between the B 12 biosynthesis and pdu clusters, is not in this location in the chromosome of Lb. reuteri.…”

How to become a uropathogen: Comparative genomic analysis of extraintestinal pathogenic Escherichia coli strains

“…typhimurium involved in coenzyme B12-dependent 1,2-propanediol catabolism. In Salmonella, the pdu operon is contiguous and coregulated with the cobalamin (B12) biosynthesis cob operon (49). The pdu͞cob genes were lost by a common ancestor of E. coli and S. enterica and reintroduced into Salmonellae by horizontal gene transfer (50,51).…”