Mutational analysis of the signal-sensing domain of ResE histidine kinase from Bacillus subtilis.
The Bacillus subtilis ResD-ResE two-component regulatory system activates genes involved in nitrate respiration in response to oxygen limitation or nitric oxide (NO). The sensor kinase ResE activates the response regulator ResD through phosphorylation, which then binds to the regulatory region of genes involved in anaerobiosis to activate their transcription. ResE is composed of an N-terminal signal input domain and a C-terminal catalytic domain. The N-terminal domain contains two transmembrane subdomains and a large extracytoplasmic loop. It also has a cytoplasmic PAS subdomain between the HAMP linker and C-terminal kinase domain. In an attempt to identify the signal-sensing subdomain of ResE, a series of deletions and amino acid substitutions were generated in the N-terminal domain. The results indicated that cytoplasmic ResE lacking the transmembrane segments and the extracytoplasmic loop retains the ability to sense oxygen limitation and NO, which leads to transcriptional activation of ResDE-dependent genes. This activity was eliminated by the deletion of the PAS subdomain, demonstrating that the PAS subdomain participates in signal reception. The study also raised the possibility that the extracytoplasmic region may serve as a second signal-sensing subdomain. This suggests that the extracytoplasmic region could contribute to amplification of ResE activity leading to the robust activation of genes required for anaerobic metabolism in B. subtilis.
Baruah
Avanti
A
Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, Oregon 97006, USA.
Lindsey
Brett
B
Zhu
Yi
Y
Nakano
Michiko M
MM
D019943:Amino Acid Substitution; D000693:Anaerobiosis; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D004268:DNA-Binding Proteins; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D000071677:Histidine Kinase; D009154:Mutation; D011494:Protein Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors
D001426:Bacterial Proteins; D003470:Culture Media; D004268:DNA-Binding Proteins; C100386:ResD protein, Bacillus subtilis; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase