title: Structural-functional relationships between terminal deoxynucleotidyltransferase and 5'-triphosphates of nucleoside analogs.
abstract: Substrate properties of nucleoside 5'-triphosphate (NTP) analogs, namely, 5'-triphosphates of L- and D-arabinonucleosides (D-FIAUTP, D-FMAUTP, and L-FMAUTP), D- and L-enantiomers of ddCTP analogs (D-ddCTP, L-ddCTP, D-FOddCTP, L-OddCTP, and L-SddCTP), and acyclic guanosine analogs (acyclovir and penciclovir) towards terminal deoxynucleotidyltransferase (TdT, EC 2.7.7.31) were studied. TdT can polymerize 5'-triphosphates of arabinonucleoside analogs (D-FIAUTP and D-FMAUTP). In contrast, L-FMAUTP is not recognized by TdT as a substrate. Kinetic parameters of D- and L-enantiomers of ddCTP analogs and 5'-triphosphates of acyclic nucleosides were evaluated. It is shown that stereospecificity of dNTP analogs and structure of the furanose residue play crucial roles in the interaction with TdT:L-enantiomers are much less potent as substrates compared to their D-counterparts. 5'-Triphosphates of acyclovir (ACVTP) and penciclovir (PCVTP) are about two orders of magnitude less effective as substrates than nucleosides bearing furanose residues, with PCVTP being a better substrate than ACVTP. It can be assumed that the hydroxyl group of PCVTP mimics the 3'-hydroxyl group of the ribose residue and plays an important role in the interaction with TdT.
authors.affiliation: Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia. kukhan86@hotmail.com
authors.forename: M K
authors.initials: MK
authors.lastname: Kukhanova
authors.forename: A V
authors.initials: AV
authors.lastname: Ivanov
authors.forename: M V
authors.initials: MV
authors.lastname: Jasko
mesh_terms: D002384:Catalysis; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism*; D007700:Kinetics; D015394:Molecular Structure; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: D009711:Nucleotides; D004253:DNA Nucleotidylexotransferase