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Peptide and amino acid metabolism is controlled by an OmpR‐family response regulator in Lactobacillus casei
Author(s) -
Alcántara Cristina,
Bäuerl Christine,
RevillaGuarinos Ainhoa,
PérezMartínez Gaspar,
Monedero Vicente,
Zúñiga Manuel
Publication year - 2016
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13299
Subject(s) - lactobacillus casei , biology , biochemistry , repressor , amino acid , response regulator , activator (genetics) , regulator , gene , operon , peptide sequence , alanine , peptide , microbiology and biotechnology , gene expression , escherichia coli , mutant , fermentation
Summary A Lactobacillus casei BL23 strain defective in an OmpR‐family response regulator encoded by LCABL_18980 (PrcR, RR11), showed enhanced proteolytic activity caused by overexpression of the gene encoding the proteinase PrtP. Transcriptomic analysis revealed that, in addition to prtP expression, PrcR regulates genes encoding peptide and amino acid transporters, intracellular peptidases and amino acid biosynthetic pathways, among others. Binding of PrcR to twelve promoter regions of both upregulated and downregulated genes, including its own promoter, was demonstrated by electrophoretic mobility shift assays showing that PrcR can act as a transcriptional repressor or activator. Phosphorylation of PrcR increased its DNA binding activity and this effect was abolished after replacement of the phosphorylatable residue Asp‐52 by alanine. Comparison of the transcript levels in cells grown in the presence or absence of tryptone in the growth medium revealed that PrcR activity responded to the presence of a complex amino acid source in the growth medium. We conclude that the PrcR plays a major role in the control of the peptide and amino acid metabolism in L. casei BL23. Orthologous prcR genes are present in most members of the Lactobacillaceae and Leuconostocaceae families. We hypothesize that they play a similar role in these bacterial groups.