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)

Genetic competence appears to be important in establishment of biofilms and tolerance of environmental insults. We report here that the development of competence is controlled at multiple levels in a complex network that includes two signal-transducing two-component systems (TCS). Using Streptococcus mutans strain UA159, we demonstrate that the histidine kinase CiaH, but not the response regulator CiaR, causes a dramatic decrease in biofilm formation and in transformation efficiency. Inactivation of comE or comD had no effect on stress tolerance, but transformability of the mutants was poor and was not restored by addition of competence-stimulating peptide (CSP). Horse serum (HS) or bovine serum albumin (BSA) had no impact on transformability of any strains. Interestingly, though, the presence of HS or BSA in combination with CSP was required for efficient induction of comD, comX, and comYA, and induction was dependent on ComDE and CiaH, but not CiaR. Inactivation of comC, encoding CSP, had no impact on transformation, and CiaH was shown to be required for optimal comC expression. This study reveals that S. mutans integrates multiple environmental signals through CiaHR and ComDE to coordinate induction of com genes and that CiaH can exert its influence through CiaR and as-yet-unidentified regulators. The results highlight critical differences in the role and regulation of CiaRH and com genes in different S. mutans isolates and between S. mutans and Streptococcus pneumoniae, indicating that substantial divergence in the role and regulation of TCS and competence genes has occurred in streptococci.
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PMID:Multilevel control of competence development and stress tolerance in Streptococcus mutans UA159. 1649 34

Incorporation of an (18)O atom into a peptide C-terminus by proteolytic cleavage in the presence of H2(18)O is one of the most effective ways of enhancing tandem mass spectrometry (MS/MS)-based de novo sequencing. Incorporation is usually accomplished by procedures including vacuum-assisted drying of tryptic peptides extracted from gels, their subsequent reconstitution in a H2(16)O/H2(18)O mixture and re-treatment with trypsin. In the present work, we propose a simplified procedure for (18)O incorporation into tryptic peptides by adding H2(18)O and trypsin to the original digest solution. In comparison to published methods, the proposed protocol for peptide de novo sequencing brings significant advantages in analysis and workflow with no deterioration in method performance. We show that labeling by this simplified method leads to a highlighting of the y-ion fragment series in the peptide matrix-assisted laser desorption/ionization (MALDI)- MS/MS data, which facilitates MS/MS data interpretation. We also prove that eliminating acid extraction of peptides from gels does not result in a decrease in sequence coverage or a qualitative loss of particular peptides detectable by MALDI-MS. The method was examined by MALDI-MS/MS on bovine serum albumin and recombinant histidine kinase CKI1 from Arabidopsis thaliana, and was verified by de novo sequencing of tryptic peptides originating from Apodemus sylvaticus salivary proteins.
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PMID:A simplified method for peptide de novo sequencing using (18)O labeling. 2489 96

Twitching motility-mediated biofilm expansion occurs via coordinated, multi-cellular collective behaviour to allow bacteria to actively expand across surfaces. Type-IV pili (T4P) are cell-associated virulence factors which mediate twitching motility via rounds of extension, surface attachment and retraction. The Chp chemosensory system is thought to respond to environmental signals to regulate the biogenesis, assembly and twitching motility function of T4P. In other well characterised chemosensory systems, methyl-accepting chemotaxis proteins (MCPs) feed environmental signals through a CheW adapter protein to the histidine kinase CheA to modulate motility. The Pseudomonas aeruginosa Chp system has an MCP PilJ and two CheW adapter proteins, PilI and ChpC, that likely interact with the histidine kinase ChpA to feed environmental signals into the system. In the current study we show that ChpC is involved in the response to host-derived signals serum albumin, mucin and oligopeptides. We demonstrate that these signals stimulate an increase in twitching motility, as well as in levels of 3'-5'-cyclic adenosine monophosphate (cAMP) and surface-assembled T4P. Interestingly, our data shows that changes in cAMP and surface piliation levels are independent of ChpC but that the twitching motility response to these environmental signals requires ChpC. Furthermore, we show that protease activity is required for the twitching motility response of P. aeruginosa to environmental signals. Based upon our data we propose a model whereby ChpC feeds these environmental signals into the Chp system, potentially via PilJ or another MCP, to control twitching motility. PilJ and PilI then modulate T4P surface levels to allow the cell to continue to undergo twitching motility. Our study is the first to link environmental signals to the Chp chemosensory system and refines our understanding of how this system controls twitching motility-mediated biofilm expansion in P. aeruginosa.
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PMID:ChpC controls twitching motility-mediated expansion of Pseudomonas aeruginosa biofilms in response to serum albumin, mucin and oligopeptides. 3247 53