scholarly journals Characterization of a Cobalt-Substituted Globin-Coupled Oxygen Sensor Histidine Kinase from Anaeromyxobacter sp. Fw109-5: Insights into Catalytic Regulation by Its Heme Coordination Structure

ACS Omega ◽  
2021 ◽  
Author(s):  
Kenichi Kitanishi ◽  
Motoyuki Shimonaka ◽  
Masaki Unno
Keyword(s):  
Histidine Kinase ◽  
Oxygen Sensor ◽  
Coordination Structure ◽  
Sensor Histidine Kinase

scholarly journals Structural characterization of Escherichia coli sensor histidine kinase EnvZ: the periplasmic C-terminal core domain is critical for homodimerization

2004 ◽  
Vol 385 (1) ◽  
pp. 255-264 ◽  
Author(s):  
Ahmad KHORCHID ◽  
Masayori INOUYE ◽  
Mitsuhiko IKURA
Keyword(s):  
Escherichia Coli ◽  
Histidine Kinase ◽  
Analytical Ultracentrifugation ◽  
Hydrophobic Interactions ◽  
Kinase Domain ◽  
Regulatory Function ◽  
Core Domain ◽  
Sensor Histidine Kinase ◽  
Helical Domain

Escherichia coli EnvZ is a membrane sensor histidine kinase that plays a pivotal role in cell adaptation to changes in extracellular osmolarity. Although the cytoplasmic histidine kinase domain of EnvZ has been extensively studied, both biochemically and structurally, little is known about the structure of its periplasmic domain, which has been implicated in the mechanism underlying its osmosensing function. In the present study, we report the biochemical and biophysical characterization of the periplasmic region of EnvZ (Ala38–Arg162). This region was found to form a dimer in solution, and to consist of two well-defined domains: an N-terminal α-helical domain and a C-terminal core domain (Glu83–Arg162) containing both α-helical and β-sheet secondary structures. Our pull-down assays and analytical ultracentrifugation analysis revealed that dimerization of the periplasmic region is highly sensitive to the presence of CHAPS, but relatively insensitive to salt concentration, thus suggesting the significance of hydrophobic interactions between the homodimeric subunits. Periplasmic homodimerization is mediated predominantly by the C-terminal core domain, while a regulatory function may be attributed mainly to the N-terminal α-helical domain, whose mutations have been shown previously to produce a high-osmolarity phenotype.

Role of Phe113 at the distal side of the heme domain of an oxygen-sensor (Ec DOS) in the characterization of the heme environment

2009 ◽  
Vol 103 (7) ◽  
pp. 989-996 ◽  
Author(s):  
Shinya Ito ◽  
Yasuyuki Araki ◽  
Atsunari Tanaka ◽  
Jotaro Igarashi ◽  
Takehiko Wada ◽  
...  
Keyword(s):  
Oxygen Sensor ◽  
Distal Side ◽  
Heme Domain

scholarly journals A Unique GTP-Dependent Sporulation Sensor Histidine Kinase in Bacillus anthracis

2008 ◽  
Vol 191 (3) ◽  
pp. 687-692 ◽  
Author(s):  
Francesca Scaramozzino ◽  
Andrea White ◽  
Marta Perego ◽  
James A. Hoch
Keyword(s):  
Bacillus Anthracis ◽  
Histidine Kinase ◽  
Catalytic Domain ◽  
Coiled Coil ◽  
Reverse Reaction ◽  
Forward Reaction ◽  
Critical Signal ◽  
Sensor Histidine Kinase ◽  
Virulence Plasmids ◽  
Kinase Catalytic Domain

ABSTRACT The Bacillus anthracis BA2291 gene codes for a sensor histidine kinase involved in the induction of sporulation. Genes for orthologs of the sensor domain of the BA2291 kinase exist in virulence plasmids in this organism, and these proteins, when expressed, inhibit sporulation by converting BA2291 to an apparent phosphatase of the sporulation phosphorelay. Evidence suggests that the sensor domains inhibit BA2291 by titrating its activating signal ligand. Studies with purified BA2291 revealed that this kinase is uniquely specific for GTP in the forward reaction and GDP in the reverse reaction. The G1 motif of BA2291 is highly modified from ATP-specific histidine kinases, and modeling this motif in the structure of the kinase catalytic domain suggested how guanine binds to the region. A mutation in the putative coiled-coil linker between the sensor domain and the catalytic domains was found to decrease the rate of the forward autophosphorylation reaction and not affect the reverse reaction from phosphorylated Spo0F. The results suggest that the activating ligand for BA2291 is a critical signal for sporulation and in a limited concentration in the cell. Decreasing the response to it either by slowing the forward reaction through mutation or by titration of the ligand by expressing the plasmid-encoded sensor domains switches BA2291 from an inducer to an inhibitor of the phosphorelay and sporulation.

DEVELOPMENT AND APPLICATION OF A CONCENTRATION PROBE FOR MIXING FLOWS TRACKING IN TURBOMACHINERY APPLICATIONS

2021 ◽  
pp. 1-35
Author(s):  
Giulia Babazzi ◽  
Tommaso Bacci ◽  
Alessio Picchi ◽  
Tommaso Fodelli ◽  
Tommaso Lenzi ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Thermal Field ◽  
Oxygen Sensor ◽  
Point Of View ◽  
Interface Plane ◽  
Tracer Gas ◽  
Precise Knowledge ◽  
Detailed Evaluation ◽  
Detection Unit

Abstract Modern gas turbines present important temperature distortions in the core-engine flowpath, mainly in the form of hot and cold streaks. As they highly influence turbines performance and lifetime, the precise knowledge of the thermal field evolution through the combustor and the high-pressure turbine is fundamental. The majority of past studies investigated streaks migrations directly examining the thermal field, while a limited amount of experimental work employed approaches based on the detection of tracer gases. The latter approach provides a more detailed evaluation of the evolution and mixing of the different flows. However, the slow time response due to the employment of sampling probes and gas analysers make the investigation extremely time consuming. In this study a commercial oxygen sensor element and its excitation/detection unit were integrated into a newly developed probe to carry out local tracer gas concentration measurements exploiting the fluorescence behaviour. The paper summarizes the probe development and calibration activities, with the characterization of its accuracy for different flow conditions. Finally, two probe applications are described: firstly the probe was used to detect tracer gas concentrations on a jet flow; afterwards it was traversed on the interface plane between a non-reactive, lean combustor simulator and the NGV cascade. The probe has proven to provide accurate and reliable measurements both from a quantitative and qualitative point of view even in highly 3D flow fields typical of gas turbines conditions.

scholarly journals Novel Family of Sensor Histidine Kinase Genes in Arabidopsis thaliana

2001 ◽  
Vol 42 (2) ◽  
pp. 231-235 ◽  
Author(s):  
Chiharu Ueguchi ◽  
Hiromi Koizumi ◽  
Tomomi Suzuki ◽  
Takeshi Mizuno
Keyword(s):  
Arabidopsis Thaliana ◽  
Histidine Kinase ◽  
Sensor Histidine Kinase
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