Open AccessA physical and functional analysis of the newly‐identified bglGPT operon of Lactobacillus plantarum
Author(s) -
Marasco Rosangela,
Salatiello Immacolata,
Felice Maurilio,
Sacco Margherita
Publication year - 2000
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2000.tb09116.x
Subject(s) - lactobacillus plantarum , operon , microbiology and biotechnology , gal operon , biology , computational biology , bacteria , genetics , gene , lactic acid , escherichia coli
A newly‐identified bglGPT operon of Lactobacillus plantarum was isolated and expressed in Escherichia coli . The sequence analysis of the cloned DNA fragment showed three open reading frames encoding (i) a 237‐amino acid protein (BglG), (ii) a 577‐amino acid protein (BglP) and (iii) a 486‐amino acid protein (BglT). BglG, BglP and BglT were shown to be homologous to the BglG family of transcriptional antiterminators, to permeases of the phosphoenolpyruvate‐dependent phosphotransferase system and to β‐glucosidases, respectively. Complementation of E. coli mutant strains showed that BglP and BglT are a permease and a β‐glucosidase active on the β‐glucosides, 5‐bromo‐4‐chloro‐3‐indolyl‐β‐ D ‐glucopyranoside and p ‐nitrophenyl‐β‐ D ‐glucoside, respectively. BglG was also shown to promote expression of a bglG – lacZ gene fusion in an E. coli bglG − background. A ribonucleic antiterminator sequence, the antiterminator‐responsive cis ‐element and a ‘catabolite responsive element’, were found downstream of the transcriptional start point. Transcription of the operon was repressed 10‐fold in L. plantarum cells grown on glucose as compared to ribose.