Kinetic studies of the predicted substrate-binding site of varicella-zoster virus thymidine kinase.

To investigate the mechanism of kinetic action and substrate recognition of varicella-zoster virus (VZV) thymidine kinase (TK), we designed and isolated a site-directed mutant VZV TK which has double amino acid substitutions, 136threonine to leucine and 137isoleucine to leucine (SDM TK). This mutant was designed to alter the substrate-binding site of the VZV TK to duplicate that of the herpes simplex virus type 2 enzyme. Kinetic studies of the activity of wild-type TK indicated that the binding order of ATP and thymidine is random and that wild-type VZV TK possessed high thymidylate kinase (TM-K) activity.

Mechanism of inhibition of DNA synthesis by 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl)uracil.

The mechanism of the inhibitory action of 1-beta-D-arabinofuranosyl-E-5-(2-bromovinyl) uracil triphosphate (BV-araUTP) on DNA synthesis by Escherichia coli DNA polymerase I Klenow fragment was studied. Acting as a chain terminator, BV-araUTP inhibited DNA synthesis by Klenow fragment more effectively than 2',3'-dideoxythymidine triphosphate (ddTTP). However, the incorporation sites of BV-araU monophosphate were restricted at consecutive dTMP sequence whereas ddTMP was incorporated at every dTMP site.

Herpesvirus saimiri has a gene specifying a homologue of the cellular membrane glycoprotein CD59.

Herpesvirus saimiri (HSV) is a T-lymphotropic tumor virus that causes fulminant lymphomas and leukemias in various New World primates other than its natural host, the squirrel monkey (Saimiri sciureus). In the course of completing the nucleotide sequence of its genome, we identified an open reading frame of 363 nucleotides, designated HVS-15, that has no detectable homology to any other viral sequences to date. HVS-15 encodes a 121-amino-acid protein which shows significant similarities to human CD59, a phosphatidyl-inositol-glycan-anchored glycoprotein involved in T-cell activation and restriction of complement-mediated lysis.

The right end of the unique region of the genome of human herpesvirus 6 U1102 contains a candidate immediate early gene enhancer and a homologue of the human cytomegalovirus US22 gene family.

The nucleotide sequence of a 12 kbp HindIII fragment (HindIII C) from the right end of the unique component of the genome of human herpesvirus 6 (HHV-6) (strain U1102) was determined. The sequence has a mean G + C content of 42% and contains approximately 28 copies of a tandemly repeated 104 to 107 bp element, which, with a single exception, contain a cleavage site for KpnI (the KpnI repeats). Each of these elements contains potential binding sites for transcription factors NF-kappa B and AP2.

Analysis of nucleotide sequence of the rightmost 43 kbp of herpesvirus saimiri (HVS) L-DNA: general conservation of genetic organization between HVS and Epstein-Barr virus.

We present an analysis of 43,658 bp of contiguous nucleotide sequence comprising the right terminal region (conventional orientation) of the unique protein-coding component (L-DNA) of the herpesvirus saimiri (HVS) genome. Within this region lie the genes encoding the 160-kDa virion protein, which is homologous to the 140-kDa membrane antigen of Epstein-Barr virus (EBV), thymidylate synthase (TS), and the immediate-early (IE) 52-kDa protein which is homologous to the EBV BMLF1 product. The 160-kDa gene of HVS lies at the right terminus of HVS L-DNA, its homologue in EBV occurring at the left terminus of the EBV genome (conventional orientation).