A new family of phosphotransferases with a P-loop motif.
In most Gram-positive bacteria, catabolite repression is mediated by a bifunctional enzyme, the histidine-containing protein kinase/phosphatase (HprK/P). Based either on its primary sequence or on its recently solved three-dimensional structure, no straightforward homology with other known proteins was found. However, we showed here that HprK/P exhibits a restricted homology with an unrelated phosphotransferase, the phosphoenolpyruvate carboxykinase. This includes notably two consecutive Asp residues from the phosphoenolpyruvate carboxykinase active site, whose equivalent residues were mutated in Bacillus subtilis HprK/P. Characterization of the corresponding mutants emphasizes the crucial role of these Asp residues in the HprK/P functioning. Furthermore, superimposition of HprK/P and phosphoenolpyruvate carboxykinase active sites supports the view that both enzymes bear significant resemblance in their overall mechanism of functioning showing that these two enzymes constitute a new family of phosphotransferases.
Galinier
Anne
A
Laboratoire de Chimie Bactérienne, UPR 9043, Institut de Biologie Structurale et Microbiologie-CNRS, 31 chemin Joseph Aiguier, 13402 Marseille, France.
Lavergne
Jean-Pierre
JP
Geourjon
Christophe
C
Fieulaine
Sonia
S
Nessler
Sylvie
S
Jault
Jean-Michel
JM
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001419:Bacteria / Q000201:enzymology; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010770:Phosphotransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D010770:Phosphotransferases