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X‐ray structure of HPr kinase: a bacterial protein kinase with a P‐loop nucleotide‐binding domain
Author(s) -
Fieulaine Sonia,
Morera Solange,
Poncet Sandrine,
Monedero Vicente,
GueguenChaig Virginie,
Galinier Anne,
Janin Joël,
Deutscher Josef,
Nessler Sylvie
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.15.3917
Subject(s) - biochemistry , kinase , biology , protein kinase domain , protein kinase a , sh3 domain , phosphotransferase , c raf , phosphatase , gtp' , adenylate kinase , cyclin dependent kinase 2 , phosphorylation , enzyme , proto oncogene tyrosine protein kinase src , gene , mutant
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 Å 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.