1kkm
From Proteopedia
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L.casei HprK/P in complex with B.subtilis P-Ser-HPr
Overview
HPr kinase/phosphorylase (HprK/P) controls the phosphorylation state of, the phosphocarrier protein HPr and regulates the utilization of carbon, sources by Gram-positive bacteria. It catalyzes both the ATP-dependent, phosphorylation of Ser-46 of HPr and its dephosphorylation by, phosphorolysis. The latter reaction uses inorganic phosphate as substrate, and produces pyrophosphate. We present here two crystal structures of a, complex of the catalytic domain of Lactobacillus casei HprK/P with, Bacillus subtilis HPr, both at 2.8-A resolution. One of the structures was, obtained in the presence of excess pyrophosphate, reversing the, phosphorolysis reaction and contains serine-phosphorylated HPr. The, complex has six HPr molecules bound to the hexameric kinase. Two adjacent, enzyme subunits are in contact with each HPr molecule, one through its, active site and the other through its C-terminal helix. In the complex, with serine-phosphorylated HPr, a phosphate ion is in a position to, perform a nucleophilic attack on the phosphoserine. Although the mechanism, of the phosphorylation reaction resembles that of eukaryotic protein, kinases, the dephosphorylation by inorganic phosphate is unique to the, HprK/P family of kinases. This study provides the structure of a protein, kinase in complex with its protein substrate, giving insights into the, chemistry of the phospho-transfer reactions in both directions.
About this Structure
1KKM is a Protein complex structure of sequences from Bacillus subtilis and Lactobacillus casei with CA and PO4 as ligands. Full crystallographic information is available from OCA.
Reference
X-ray structure of a bifunctional protein kinase in complex with its protein substrate HPr., Fieulaine S, Morera S, Poncet S, Mijakovic I, Galinier A, Janin J, Deutscher J, Nessler S, Proc Natl Acad Sci U S A. 2002 Oct 15;99(21):13437-41. Epub 2002 Oct 1. PMID:12359875
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