4bix | pdb_00004bix
Crystal structure of CpxAHDC (monoclinic form 1)
Structural highlights
FunctionCPXA_ECOLI This protein is involved in several diverse cellular processes, such as the functioning of acetohydroxyacid synthetase I, in the biosynthesis of isoleucine and valine, the TraJ protein activation activity for tra gene expression in F plasmid, and the synthesis, translocation, or stability of cell envelope proteins. Activates CpxR by phosphorylation. Publication Abstract from PubMedHistidine kinases (HKs) are dimeric receptors that participate in most adaptive responses to environmental changes in prokaryotes. Although it is well established that stimulus perception triggers autophosphorylation in many HKs, little is known on how the input signal propagates through the HAMP domain to control the transient interaction between the histidine-containing and ATP-binding domains during the catalytic reaction. Here we report crystal structures of the full cytoplasmic region of CpxA, a prototypical HK involved in Escherichia coli response to envelope stress. The structural ensemble, which includes the Michaelis complex, unveils HK activation as a highly dynamic process, in which HAMP modulates the segmental mobility of the central HK alpha-helices to promote a strong conformational and dynamical asymmetry that characterizes the kinase-active state. A mechanical model based on our structural and biochemical data provides insights into HAMP-mediated signal transduction, the autophosphorylation reaction mechanism, and the symmetry-dependent control of HK kinase/phosphatase functional states. Segmental helical motions and dynamical asymmetry modulate histidine kinase autophosphorylation.,Mechaly AE, Sassoon N, Betton JM, Alzari PM PLoS Biol. 2014 Jan 28;12(1):e1001776. doi: 10.1371/journal.pbio.1001776., eCollection 2014 Jan. PMID:24492262[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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