8dvq
CA domain of VanSA histidine kinase
Structural highlights
FunctionVANS_ENTFC Member of the two-component regulatory system VanS/VanR. Activates the transcription of vanH, vanA and vanX in response to vancomycin which results in vancomycin resistance. VanS activates VanR by phosphorylation. Publication Abstract from PubMedThe VanRS two-component system regulates the resistance phenotype of vancomycin-resistant enterococci. VanS is a sensor histidine kinase that responds to the presence of vancomycin by autophosphorylating and subsequently transferring the phosphoryl group to the response regulator, VanR. The phosphotransfer activates VanR as a transcription factor, which initiates the expression of resistance genes. Structural information about VanS proteins has remained elusive, hindering the molecular-level understanding of their function. Here, we present X-ray crystal structures for the catalytic and ATP-binding (CA) domains of two VanS proteins, derived from vancomycin-resistant enterococci types A and C. Both proteins adopt the canonical Bergerat fold that has been observed for CA domains of other prokaryotic histidine kinases. We attempted to determine structures for the nucleotide-bound forms of both proteins; however, despite repeated efforts, these forms could not be crystallized, prompting us to measure the proteins' binding affinities for ATP. Unexpectedly, both CA domains displayed low affinities for the nucleotide, with K(D) values in the low millimolar range. Since these K(D) values are comparable to intracellular ATP concentrations, this weak substrate binding could reflect a way of regulating expression of the resistance phenotype. Structure of VanS from vancomycin-resistant enterococci: A sensor kinase with weak ATP binding.,Grasty KC, Guzik C, D'Lauro EJ, Padrick SB, Beld J, Loll PJ J Biol Chem. 2023 Mar;299(3):103001. doi: 10.1016/j.jbc.2023.103001. Epub 2023 , Feb 9. PMID:36764524[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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