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Control of bacterial chemotaxis by heme nitric oxide/oxygen proteins (614.2)
Author(s) -
Hespen Charles,
Marletta Michael
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.614.2
Subject(s) - chemotaxis , obligate anaerobe , response regulator , bacteria , heme , biochemistry , nitric oxide , histidine kinase , proteobacteria , microbiology and biotechnology , biology , chemistry , biophysics , histidine , enzyme , bacterial protein , receptor , genetics , 16s ribosomal rna , endocrinology
Hemoprotein gas sensors are integral components in the cellular machinery to recognize and rapidly respond to dynamic changes in redox state and the concentration of reactive gases. Heme‐Nitric oxide/Oxygen sensing (H‐NOX) proteins, found in both eukaryotes and bacteria, respond to NO in facultative aerobic bacteria, and regulate biofilm formation through the control of a complex two‐component signaling network. H‐NOX proteins are also found in obligate anaerobic bacteria, predominantly Clostridia, and are fused to Methyl‐accepting Chemotaxis Proteins (MCPs). MCP domains control the chemotaxis‐signaling pathway, which guides bacteria toward beneficial molecules (attractants) and away from harmful molecules (repellents). Obligate anaerobe H‐NOXs contain a conserved H‐bonding network associated with the formation of a stable O2 complex. Because NO and O2 are both toxic to obligate anaerobes, the H‐NOX‐MCP likely senses one or both of these gases and activates a repellent response in bacteria. A gas sensing chemoreceptor has not yet been identified in Clostridia, a class of organisms whose ability to rapidly avoid increasing concentrations of O2 is vital for survival. To characterize how gases affect the H‐NOX‐MCP's control of chemotaxis, the chemotaxis pathway of Clostridium sporogenes has been reconstituted in vitro. Changes in activity of the chemotaxis histidine kinase, CheA, were measured in different H‐NOX‐MCP heme ligation states. Grant Funding Source : Supported by NIH Ruth L. Kirchstein NRSA