Cloning, Sequence Analysis, and Characterization of the Genes Involved in Isoprimeverose Metabolism in Lactobacillus pentosus - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Accéder directement au contenu
Article Dans Une Revue Journal of Bacteriology Année : 1998

Cloning, Sequence Analysis, and Characterization of the Genes Involved in Isoprimeverose Metabolism in Lactobacillus pentosus

Stéphane Chaillou
B. Christien Lokman
  • Fonction : Auteur
Rob Leer
  • Fonction : Auteur
Clara Posthuma
  • Fonction : Auteur
Pieter Postma
  • Fonction : Auteur
Peter Pouwels
  • Fonction : Auteur

Résumé

ABSTRACT Two genes, xylP and xylQ , from the xylose regulon of Lactobacillus pentosus were cloned and sequenced. Together with the repressor gene of the regulon, xylR , the xylPQ genes form an operon which is inducible by xylose and which is transcribed from a promoter located 145 bp upstream of xylP . A putative xylR binding site ( xylO ) and a cre -like element, mediating CcpA-dependent catabolite repression, were found in the promoter region. L. pentosus mutants in which both xylP and xylQ (LPE1) or only xylQ (LPE2) was inactivated retained the ability to ferment xylose but were impaired in their ability to ferment isoprimeverose (α- d -xylopyranosyl-(1,6)- d -glucopyranose). Disruption of xylQ resulted specifically in the loss of a membrane-associated α-xylosidase activity when LPE1 or LPE2 cells were grown on xylose. In the membrane fraction of wild-type bacteria, α-xylosidase could catalyze the hydrolysis of isoprimeverose and p -nitrophenyl-α- d -xylopyranoside with apparent K m and V max values of 0.2 mM and 446 nmol/min/mg of protein, and 1.3 mM and 54 nmol/min/mg of protein, respectively. The enzyme could also hydrolyze the α-xylosidic linkage in xyloglucan oligosaccharides, but neither methyl-α- d -xylopyranoside nor α-glucosides were substrates. Glucose repressed the synthesis of α-xylosidase fivefold, and 80% of this repression was released in an L. pentosus ΔccpA mutant. The α-xylosidase gene was also expressed in the absence of xylose when xylR was disrupted.

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Bactériologie

Dates et versions

hal-03376461 , version 1 (13-10-2021)

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Stéphane Chaillou, B. Christien Lokman, Rob Leer, Clara Posthuma, Pieter Postma, et al.. Cloning, Sequence Analysis, and Characterization of the Genes Involved in Isoprimeverose Metabolism in Lactobacillus pentosus. Journal of Bacteriology, 1998, 180 (9), pp.2312-2320. ⟨10.1128/JB.180.9.2312-2320.1998⟩. ⟨hal-03376461⟩

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