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Structure of VanS from Vancomycin-Resistant Enterococci: A Sensor Kinase with Weak ATP Binding
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Structure of VanS from Vancomycin-Resistant Enterococci: A Sensor Kinase with Weak ATP Binding

Kimberly Grasty, Claudia Guzik, Elizabeth D'lauro, Shae Padrick, Joris Beld and Patrick Loll
bioRxiv
13 Dec 2022
DOI: https://doi.org/10.1101/2022.12.12.520123
url
https://doi.org/10.1101/2022.12.12.520123View
Submitted Restricted CC BY-NC-ND V4.0

Abstract

Histidine Histidine kinase Phenotypes Proteins Vancomycin
The VanRS two-component system regulates the resistance phenotype of vancomycin-resistant enterococci (VRE). 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 VRE 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 KD values in the low millimolar range. Since these KD values are comparable to intracellular ATP concentrations, this weak substrate binding could reflect a way of regulating expression of the resistance phenotype. Competing Interest Statement The authors have declared no competing interest.

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