Structural highlights
Function
[KIPI_BACSU] Is a potent inhibitor of the autophosphorylation reaction of kinase A and its reverse reaction, but does not inhibit phosphate transfer to the Spo0F response regulator once kinase A is phosphorylated. KipI is an inhibitor of the catalytic domain of kinase A affecting the ATP/ADP reactions and not the phosphotransferase functions of this domain. The inhibition is noncompetitive with respect to ATP.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The sensor histidine kinase A (KinA) from Bacillus subtilis triggers a phosphorelay that activates sporulation. The antikinase KipI prevents sporulation by binding KinA and inhibiting the autophosphorylation reaction. Using neutron contrast variation, mutagenesis, and fluorescence data, we show that two KipI monomers bind via their C-domains at a conserved proline in the KinA dimerization and histidine-phosphotransfer (DHp) domain. Our crystal structure of the KipI C-domain reveals the binding motif has a distinctive hydrophobic groove formed by a five-stranded antiparallel beta-sheet; a characteristic of the cyclophilin family of proteins that bind prolines and often act as cis-trans peptidyl-prolyl isomerases. We propose that the DHp domain of KinA transmits conformational signals to regulate kinase activity via this proline-mediated interaction. Given that both KinA and KipI homologues are widespread in the bacterial kingdom, this mechanism has broad significance in bacterial signal transduction.
Histidine kinase regulation by a cyclophilin-like inhibitor.,Jacques DA, Langley DB, Jeffries CM, Cunningham KA, Burkholder WF, Guss JM, Trewhella J J Mol Biol. 2008 Dec 12;384(2):422-35. Epub 2008 Sep 16. PMID:18823995[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Jacques DA, Langley DB, Jeffries CM, Cunningham KA, Burkholder WF, Guss JM, Trewhella J. Histidine kinase regulation by a cyclophilin-like inhibitor. J Mol Biol. 2008 Dec 12;384(2):422-35. Epub 2008 Sep 16. PMID:18823995 doi:10.1016/j.jmb.2008.09.017
