1jb1

Publication Abstract from PubMed

HPr kinase/phosphatase (HprK/P) is a key regulatory enzyme controlling carbon metabolism in Gram- positive bacteria. It catalyses the ATP-dependent phosphorylation of Ser46 in HPr, a protein of the phosphotransferase system, and also its dephosphorylation. HprK/P is unrelated to eukaryotic protein kinases, but contains the Walker motif A characteristic of nucleotide-binding proteins. We report here the X-ray structure of an active fragment of Lactobacillus casei HprK/P at 2.8 A resolution, solved by the multiwavelength anomalous dispersion method on a seleniated protein (PDB code 1jb1). The protein is a hexamer, with each subunit containing an ATP-binding domain similar to nucleoside/nucleotide kinases, and a putative HPr-binding domain unrelated to the substrate-binding domains of other kinases. The Walker motif A forms a typical P-loop which binds inorganic phosphate in the crystal. We modelled ATP binding by comparison with adenylate kinase, and designed a tentative model of the complex with HPr based on a docking simulation. The results confirm that HprK/P represents a new family of protein kinases, first identified in bacteria, but which may also have members in eukaryotes.

X-ray structure of HPr kinase: a bacterial protein kinase with a P-loop nucleotide-binding domain.,Fieulaine S, Morera S, Poncet S, Monedero V, Gueguen-Chaignon V, Galinier A, Janin J, Deutscher J, Nessler S EMBO J. 2001 Aug 1;20(15):3917-27. PMID:11483495^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.