Cloning, Sequence Analysis, and Characterization of the Genes Involved in Isoprimeverose Metabolism in Lactobacillus pentosus
| Autor: | R.J. Leer, B.C. Lokman, Pieter W. Postma, Peter H. Pouwels, Stéphane Chaillou, C. Posthuma |
|---|---|
| Přispěvatelé: | Universiteit van Amsterdam (UvA) |
| Rok vydání: | 1998 |
| Předmět: |
molecular cloning
Operon Mutant Catabolite repression Xylose Disaccharides Substrate Specificity chemistry.chemical_compound Glycosides Cloning Molecular fermentation Bacteria (microorganisms) 0303 health sciences Symporters article gene control gene expression regulation Lactobacillus pentosus Prokaryota Xylosidases priority journal Posibacteria Biochemistry CCPA bacterial gene Physiology and Metabolism Molecular Sequence Data Repressor Biology Microbiology repressor gene 03 medical and health sciences Bacterial Proteins carbohydrate metabolism Amino Acid Sequence Molecular Biology 030304 developmental biology nonhuman Base Sequence Sequence Homology Amino Acid 030306 microbiology bacterial metabolism nucleotide sequence Sequence Analysis DNA [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology Molecular biology Cell Compartmentation lactobacillus Lactobacillus Regulon chemistry Genes Bacterial regulon disaccharide Carrier Proteins |
| Zdroj: | Journal of Bacteriology Journal of Bacteriology, American Society for Microbiology, 1998, 180 (9), pp.2312-2320. ⟨10.1128/JB.180.9.2312-2320.1998⟩ Journal of Bacteriology, 9, 180, 2312-2320 |
| ISSN: | 1098-5530 0021-9193 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|