title: Characterization of a putative oomycete taurocyamine kinase: Implications for the evolution of the phosphagen kinase family.
abstract: Phosphagen kinases (PKs) are known to be distributed throughout the animal kingdom, but have recently been discovered in some protozoan and bacterial species. Within animal species, these enzymes play a critical role in energy homeostasis by catalyzing the reversible transfer of a high-energy phosphoryl group from Mg⋅ATP to an acceptor molecule containing a guanidinium group. In this work, a putative PK gene was identified in the oomycete Phytophthora sojae that was predicted, based on sequence homology, to encode a multimeric hypotaurocyamine kinase. The recombinant P. sojae enzyme was purified and shown to catalyze taurocyamine phosphorylation efficiently (kcat/KM (taurocyamine) = 2 × 10(5) M(-1) s(-1)) and glycocyamine phosphorylation only weakly (kcat/KM (glycocyamine) = 2 × 10(2) M(-1) s(-1)), but lacked any observable kinase activity with the more ubiquitous guanidinium substrates, creatine or arginine. Additionally, the enzyme was observed to be dimeric but lacked cooperativity between the subunits in forming a transition state analog complex. These results suggest that protozoan PKs may exhibit more diversity in substrate specificity than was previously thought.
authors: Program in Biochemistry and Molecular Biology, The College of Wooster, Wooster, OH 44691, USA.
authors: Allyson
authors: A
authors: Palmer
authors: Brittany N
authors: BN
authors: Begres
authors: Jason M
authors: JM
authors: Van Houten
authors: Mark J
authors: MJ
authors: Snider
authors: Dean
authors: D
authors: Fraga
mesh_terms: D000595:Amino Acid Sequence; D055162:Biocatalysis; D019143:Evolution, Molecular; D005998:Glycine / Q000031:analogs & derivatives / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D017852:Phosphotransferases (Nitrogenous Group Acceptor) / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D010838:Phytophthora / Q000201:enzymology* / Q000235:genetics*; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D016415:Sequence Alignment; D013379:Substrate Specificity; D013654:Taurine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D013654:Taurine; C009558:taurocyamine; D017852:Phosphotransferases (Nitrogenous Group Acceptor); C022716:taurocyamine kinase; C004946:glycocyamine; D005998:Glycine
keywords: Oomycota; Phosphagen kinase; Phytophthora sojae; Stramenopile; Taurocyamine kinase