Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.13.3 (histidine kinase)
 2,405 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Production of the bacteriocin sakacin P by Lactobacillus sake LTH673 is dependent on a secreted 19-residue peptide pheromone (IP-673). The gene encoding IP-673 (sppIP) was identified and sequenced. SppIP was shown to be co-transcribed with genes encoding a histidine kinase (sppK) and a response regulator (sppR) typical for signal transduction in bacteria. Further sequencing and transcription studies have shown that IP-673 induces transcription of its own gene and of what are often considered to be all genes necessary for bacteriocin production and immunity. Studies with a reporter gene showed that the promoter in front of the sakacin P structural gene (sppA) is strictly regulated. The promoter in front of sppIP turned out to be less strictly regulated, and low basal promoter activity could be detected in uninduced cells. Bacteriocin production in Bac isolates of L. plantarum C11 could be induced by the non-cognate IP-673 only after the introduction of sppK, indicating that sppK encodes the pheromone receptor. These results show that bacteriocin production in lactobacilli is regulated using a short, strain-specific peptide pheromone. Growth conditions were shown to have considerable effects on the functionality of this regulatory mechanism.
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PMID:Pheromone-induced production of antimicrobial peptides in Lactobacillus. 938 59

C protein beta antigen (Bac), a surface protein of group B streptococci (GBS), is known to concurrently bind the Fc portion of IgA and factor H (FH). The authors' previous work has demonstrated that mRNA expression levels show diversity among clonally related strains containing genes (bac) encoding Bac, with high expression noted in invasive strains. In this study, the bac gene and upstream regions containing putative promoters, three ORFs and an IS1381 insertion sequence were characterized. Three invasive strains showed high bac expression levels and did not show any notable mutations except one strain producing Bac that was able to bind FH but not IgA. A deletion of 51 amino acid residues, including part of the Bac IgA-binding region, was identified and hypothesized to contribute to the loss of the IgA-binding ability of this strain. A vaginal strain that showed somewhat higher bac expression levels and produced Bac lacking immunoreactivity contained an 11 bp deletion, which generated a premature termination codon, in the region preceding the IgA-binding region. In another vaginal strain that did not express bac, disruption of the upstream ORFs of the sensor histidine kinase and DNA-binding response regulator, due to frameshift mutations, was noted although it is not known whether these proteins directly affect bac expression levels. An IS1381 insertion into the promoter region was found in another vaginal strain that showed low expression levels and produced Bac with a significantly larger proline-rich repeat region. These results demonstrate considerable genetic diversity of the bac and upstream regions of invasive and noninvasive GBS, which may contribute to the variability of bac expression levels among those strains.
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PMID:Genetic diversity of the C protein beta-antigen gene and its upstream regions within clonally related groups of type Ia and Ib group B streptococci. 1651 56