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Exp Parasitol. 2013 Dec;135(4):695-700. doi: 10.1016/j.exppara.2013.10.008. Epub 2013 Oct 30.

The role of Y84 on domain 1 and Y87 on domain 2 of Paragonimus westermani taurocyamine kinase: Insights on the substrate binding mechanism of a trematode phosphagen kinase.

Author information

1
Department of Environmental Health Sciences, Kochi University, Kochi 783-8505, Japan; Department of Immunology, Research Institute for Tropical Medicine, Muntinlupa 1781, Philippines.

Abstract

The two-domain taurocyamine kinase (TK) from Paragonimus westermani was suggested to have a unique substrate binding mechanism. We performed site-directed mutagenesis on each domain of this TK and compared the kinetic parameters Km(Tc) and Vmax with that of the wild-type to determine putative amino acids involved in substrate recognition and binding. Replacement of Y84 on domain 1 and Y87 on domain 2 with R resulted in the loss of activity for the substrate taurocyamine. Y84E mutant has a dramatic decrease in affinity and activity for taurocyamine while Y87E has completely lost catalytic activity. Substituting H and I on the said positions also resulted in significant changes in activity. Mutation of the residues A59 on the GS region of domain 1 also caused significant decrease in affinity and activity while mutation on the equivalent position on domain 2 resulted in complete loss of activity.

KEYWORDS:

AK; CK; GK; LK; PK; Paragonimus westermani; Phosphagen kinase; Site-directed mutagenesis; TK; Taurocyamine kinase; Trematode; arginine kinase; creatine kinase; glycocyamine kinase; lombricine kinase; phosphagen kinase; taurocyamine kinase

PMID:
24184078
DOI:
10.1016/j.exppara.2013.10.008
[Indexed for MEDLINE]

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