Dataset Information

Comparative sequence analysis of acid sensitive/resistance proteins in Escherichia coli and Shigella flexneri.

ABSTRACT: The molecular basis for the survival of bacteria under extreme conditions in which growth is inhibited is a question of great current interest. A preliminary study was carried out to determine residue pattern conservation among the antiporters of enteric bacteria, responsible for extreme acid sensitivity especially in Escherichia coli and Shigella flexneri. Here we found the molecular evidence that proved the relationship between E. coli and S. flexneri. Multiple sequence alignment of the gadC coded acid sensitive antiporter showed many conserved residue patterns at regular intervals at the N-terminal region. It was observed that as the alignment approaches towards the C-terminal, the number of conserved residues decreases, indicating that the N-terminal region of this protein has much active role when compared to the carboxyl terminal. The motif, FHLVFFLLLGG, is well conserved within the entire gadC coded protein at the amino terminal. The motif is also partially conserved among other antiporters (which are not coded by gadC) but involved in acid sensitive/resistance mechanism. Phylogenetic cluster analysis proves the relationship of Escherichia coli and Shigella flexneri. The gadC coded proteins are converged as a clade and diverged from other antiporters belongs to the amino acid-polyamine-organocation (APC) superfamily.

SUBMITTER: Manikandan S

PROVIDER: S-EPMC2255067 | biostudies-literature | 2007

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Comparative sequence analysis of acid sensitive/resistance proteins in Escherichia coli and Shigella flexneri.

Manikandan Selvaraj S Balaji Seetharaaman S Kumar Anil A Kumar Rita R

Bioinformation 20071211 4

The molecular basis for the survival of bacteria under extreme conditions in which growth is inhibited is a question of great current interest. A preliminary study was carried out to determine residue pattern conservation among the antiporters of enteric bacteria, responsible for extreme acid sensitivity especially in Escherichia coli and Shigella flexneri. Here we found the molecular evidence that proved the relationship between E. coli and S. flexneri. Multiple sequence alignment of the gadC c ...[more]

PMID: 21670792

Similar Datasets

Project description:Escherichia coli K-12 strains and Shigella flexneri grown to stationary phase can survive several hours at pH 2 to 3, which is considerably lower than the acid limit for growth (about pH 4.5). A 1.3-kb fragment cloned from S. flexneri conferred acid resistance on acid-sensitive E. coli HB101; sequence data identified the fragment as a homolog of rpoS, the growth phase-dependent sigma factor sigma 38. The clone also conferred acid resistance on S. flexneri rpoS::Tn10 but not on Salmonella typhimurium. E. coli and S. flexneri strains containing wild-type rpoS maintained greater internal pH in the face of a low external pH than strains lacking functional rpoS, but the ability to survive at low pH did not require maintenance of a high transmembrane pH difference. Aerobic stationary-phase cultures of E. coli MC4100 and S. flexneri 3136, grown initially at an external pH range of 5 to 8, were 100% acid resistant (surviving 2 h at pH 2.5). Aerobic log-phase cultures grown at pH 5.0 were acid resistant; survival decreased 10- to 100-fold as the pH of growth was increased to pH 8.0. Extended growth in log phase also decreased acid resistance substantially. Strains containing rpoS::Tn10 showed partial acid resistance when grown at pH 5 to stationary phase; log-phase cultures showed < 0.01% acid resistance. When grown anaerobically at low pH, however, the rpoS::Tn10 strains were acid resistant. E. coli MC4100 also showed resistance at alkaline pH outside the growth range (base resistance). Significant base resistance was observed up to pH 10.2. Base resistance was diminished by rpoS::Tn10 and by the presence of Na+. Base resistance was increased by an order of magnitude for stationary-phase cultures grown in moderate base (pH 8) compared with those grown in moderate acid (pH 5). Anaerobic growth partly restored base resistance in cultures grown at pH 5 but not in those grown at pH 8. Thus, both acid resistance and base resistance show dependence on growth pH and are regulated by rpoS under certain conditions. For acid resistance, and in part for base resistance, the rpoS requirement can be overcome by anaerobic growth in moderate acid.

Dataset Information

Comparative sequence analysis of acid sensitive/resistance proteins in Escherichia coli and Shigella flexneri.

Publications

Comparative sequence analysis of acid sensitive/resistance proteins in Escherichia coli and Shigella flexneri.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets