Lactobacillus reuteri DSM 20016 produces cobalamin-dependent diol dehydratase in metabolosomes and metabolizes 1,2-propanediol by disproportionation.

Journal Article (Journal Article)

A Lactobacillus reuteri strain isolated from sourdough is known to produce the vitamin cobalamin. The organism requires this for glycerol cofermentation by a cobalamin-dependent enzyme, usually termed glycerol dehydratase, in the synthesis of the antimicrobial substance reuterin. We show that the cobalamin-synthesizing capacity of another L. reuteri strain (20016, the type strain, isolated from the human gut and recently sequenced as F275) is genetically and phenotypically linked, as in the Enterobacteriaceae, to the production of a cobalamin-dependent enzyme which is associated with a bacterial microcompartment (metabolosome) and known as diol dehydratase. We show that this enzyme allows L. reuteri to carry out a disproportionation reaction converting 1,2-propanediol to propionate and propanol. The wide distribution of this operon suggests that it is adapted to horizontal transmission between bacteria. However, there are significant genetic and phenotypic differences between the Lactobacillus background and the Enterobacteriaceae. Electron microscopy reveals that the bacterial microcompartment in L. reuteri occupies a smaller percentage of the cytoplasm than in gram-negative bacteria. DNA sequence data show evidence of a regulatory control mechanism different from that in gram-negative bacteria, with the presence of a catabolite-responsive element (CRE) sequence immediately upstream of the pdu operon encoding diol dehydratase and metabolosome structural genes in L. reuteri. The metabolosome-associated diol dehydratase we describe is the only candidate glycerol dehydratase present on inspection of the L. reuteri F275 genome sequence.

Full Text

Duke Authors

Cited Authors

  • Sriramulu, DD; Liang, M; Hernandez-Romero, D; Raux-Deery, E; Lünsdorf, H; Parsons, JB; Warren, MJ; Prentice, MB

Published Date

  • July 2008

Published In

Volume / Issue

  • 190 / 13

Start / End Page

  • 4559 - 4567

PubMed ID

  • 18469107

Pubmed Central ID

  • PMC2446795

Electronic International Standard Serial Number (EISSN)

  • 1098-5530

International Standard Serial Number (ISSN)

  • 0021-9193

Digital Object Identifier (DOI)

  • 10.1128/jb.01535-07


  • eng