1 research outputs found
Mapping the H‑NOX/HK Binding Interface in <i>Vibrio cholerae</i> by Hydrogen/Deuterium Exchange Mass Spectrometry
Heme-nitric
oxide/oxygen binding (H-NOX) proteins are a group of hemoproteins
that bind diatomic gas ligands such as nitric oxide (NO) and oxygen
(O<sub>2</sub>). H-NOX proteins typically regulate histidine kinases
(HK) located within the same operon. It has been reported that NO-bound
H-NOXs inhibit cognate histidine kinase autophosphorylation in bacterial
H-NOX/HK complexes; however, a detailed mechanism of NO-mediated regulation
of the H-NOX/HK activity remains unknown. In this study, the binding
interface of <i>Vibrio cholerae</i> (<i>Vc</i>) H-NOX/HK complex was characterized by hydrogen/deuterium exchange
mass spectrometry (HDX-MS) and further validated by mutagenesis, leading
to a new model for NO-dependent kinase inhibition. A conformational
change in <i>Vc</i> H-NOX introduced by NO generates a new
kinase-binding interface, thus locking the kinase in an inhibitory
conformation