title: Substrate specificity of feline and canine herpesvirus thymidine kinase.
abstract: The thymidine kinases from feline herpesvirus (FHV TK) and canine herpesvirus (CHV TK) were cloned and characterized. The two proteins are closely sequence-related to each other and also to the herpes simplex virus type 1 thymidine kinase (HSV-1 TK). Although FHV TK and CHV TK have a level of identity of 31 and 35%, respectively, with HSV-1 TK, and a general amino acid similarity of approximately 54% with HSV-1 TK, they do not recognize the same broad range of substrates as HSV-1 TK does. Instead the substrate recognition is restricted to dThd and pyrimidine analogs such as 1-beta-d-arabinofuranosylthymine (araT), 3'-azido-2',3'-dideoxythymidine (AZT) and (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU). FHV TK and CHV TK differ in substrate recognition from mammalian cytosolic thymidine kinase 1 (TK1) in that TK1 does not phosphorylate BVDU and they also differ from mammalian mitochondrial thymidine kinase 2 (TK2), which, in addition to thymidine and thymidine analogs also phosphorylates dCyd. Although the nucleoside analog BVDU was a good substrate for FHV and CHV TK, the compound was poorly inhibitory to virus-induced cytopathic effect in FHV- and CHV-infected cells. The reason is likely the poor, if any, thymidylate kinase activity of FHV and CHV TK, which in HSV-1 TK-expressing cells convert BVDU-MP to its 5'-diphosphate derivative.
authors.affiliation: Department of Laboratory Medicine, Karolinska Institute, S-141 86 Stockholm, Sweden. nicola.solaroli@ki.se
authors.forename: N
authors.initials: N
authors.lastname: Solaroli
authors.forename: M
authors.initials: M
authors.lastname: Johansson
authors.forename: L
authors.initials: L
authors.lastname: Persoons
authors.forename: J
authors.initials: J
authors.lastname: Balzarini
authors.forename: A
authors.initials: A
authors.lastname: Karlsson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D002460:Cell Line; D003001:Cloning, Molecular; D004285:Dogs; D006564:Herpesviridae / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D011743:Pyrimidines / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013936:Thymidine / Q000031:analogs & derivatives / Q000378:metabolism; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D011743:Pyrimidines; D014764:Viral Proteins; C105339:thymidine kinase 2; C099241:thymidine kinase, Canid herpesvirus 1; D013937:Thymidine Kinase; C092717:thymidine kinase 1; D013936:Thymidine