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Proteomic characterization of the acid tolerance response in L actobacillus delbrueckii subsp. bulgaricus CAUH1 and functional identification of a novel acid stress‐related transcriptional regulator L db0677
Author(s) -
Zhai Zhengyuan,
Douillard François P.,
An Haoran,
Wang Guohong,
Guo Xinghua,
Luo Yunbo,
Hao Yanling
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12280
Subject(s) - biology , regulator , lactococcus lactis , proteome , transcriptional regulation , biochemistry , heterologous , response regulator , proteomics , ribosomal protein , gene , gene expression , microbiology and biotechnology , rna , lactic acid , ribosome , genetics , bacteria , mutant
Summary To overcome the deleterious effects of acid stress, Lactobacillus delbrueckii subsp. bulgaricus ( L . bulgaricus ) elicits an adaptive response to acid stress. In this study, proteomics approach complemented by transcriptional analysis revealed some cellular changes in L . bulgaricus CAUH1 during acid adaptation. We observed an increase of glycolysis‐associated proteins, promoting an optimal utilization of carbohydrates. Also, rerouting of the pyruvate metabolism to fatty acid biosynthesis was observed, indicating a possible modification of the cell membrane rigidity and impermeability. In addition, expression of ribosomal protein S1 ( RpsA ) was repressed; however, the expression of EF ‐ Tu , EF ‐ G and TypA was up‐regulated at both protein and transcript levels. This suggests a reduction of protein synthesis in response to acid stress along with possible enhancement of the translational accuracy and protein folding. It is noteworthy that the putative transcriptional regulator L db0677 was 1.84‐fold up‐regulated. Heterologous expression of L db0677 was shown to significantly enhance acid resistance in host strain L actococcus lactis . To clarify its role in transcriptional regulation network, the DNA ‐binding specificity of L db0677 was determined using bacterial one‐hybrid and electrophoretic mobility shift assay. The identification of a binding motif ( SSTAGACR ) present in the promoter regions of 22 genes indicates that it might function as a major regulator in acid stress response in L . bulgaricus .