Activation of Bacillus subtilis Ugd by the BY-kinase PtkA proceeds via phosphorylation of its residue tyrosine 70.
The phosphorylation-dependent activation of bacterial UDP-glucose dehydrogenases by BY-kinases has been previously described in several bacterial model organisms, but the identity of phosphorylated tyrosine(s) and the exact activation mechanism remained unknown. A recent site-specific phosphoproteomic study indicated that tyrosine 70 is phosphorylated in the Bacillus subtilis UDP-glucose dehydrogenase Ugd. In this study we confirm that this tyrosine 70 is indeed the main residue phosphorylated by the cognate BY-kinase PtkA. Homology-based modeling of the Ugd structure using structures from UDP-glucose/GDP-mannose dehydrogenases revealed that this residue is in close proximity to the NAD-binding site. We identified lysine 108 as the second important residue involved in Ugd activation. Enzymatic characterization of the Ugd proteins mutated in residues tyrosine 70 or lysine 108 suggested a phosphorylation-based regulatory mechanism. This study represents the first attempt to understand the activation of a bacterial enzyme by tyrosine phosphorylation at the molecular level.
Petranovic
Dina
D
Technical University of Denmark, Biosys, Center for Microbial Biotechnology, Lyngby, Denmark.
Grangeasse
Christophe
C
Macek
Boris
B
Abdillatef
Mohammad
M
Gueguen-Chaignon
Virginie
V
Nessler
Sylvie
S
Deutscher
Josef
J
Mijakovic
Ivan
I
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001412:Bacillus subtilis / Q000201:enzymology* / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D014443:Tyrosine / Q000378:metabolism; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000378:metabolism*
D014443:Tyrosine; D014533:Uridine Diphosphate Glucose Dehydrogenase; D011494:Protein Kinases