当前位置： SCI文献检索 > ANTIMICROBIAL AGENTS AND CHEMOTHERAPY期刊下所有文献 > Clinical isolate of herpes simplex virus type 2 that induces a thymidine kinase with altered substrate specificity.

Clinical isolate of herpes simplex virus type 2 that induces a thymidine kinase with altered substrate specificity.

Abstract：

:In vitro and in vivo studies were done on a herpes simplex virus type 2 strain recovered from a patient on acyclovir (ACV) which was ACV resistant but expressed thymidine (dThd) kinase (EC 2.7.1.21) activity. Plaque-purified clones derived from the original clinical sample were heterogeneous with respect to plaque size and drug susceptibility. The heterogeneity of this viral mixture was also evident from varied 125I-labeled 5-iodo-2'-deoxycytidine autoradiographic patterns and from varied expression of dThd kinase-associated phosphorylating activities. Four clones from this mixture were 1-beta-D-arabinofuranosylthymine (ara-T) susceptible and ACV resistant. Extracts of cells infected with these clones catalyzed the phosphorylation of ara-T but little of ACV. The virus-coded dThd kinase was purified from one of these clones to determine whether its substrate specificity was altered. The amount of virus-coded dThd phosphorylating activity with the cell extracts was estimated to be sevenfold lower with the resistant clone than with the MS strain of herpes simplex virus type 2. The dThd kinase eluted from a dThd-agarose affinity column under the same conditions with extracts from both sources and substrate saturations of both enzymes by acyclic nucleoside analog phosphate acceptors were classical hyperbolic functions. However, there were significant differences in the kinetic parameters of substrates between the two enzymes. Apparent Km (Km') values for dThd, deoxycytidine, ara-T, ACV, and the acyclic guanosine analog 9-[[2-hydroxyl-1-(hydroxymethyl)ethoxy]methyl]guaine (BW B759U) were 2- to 60-fold higher with the variant enzyme than with the enzyme from laboratory strain MS. Comparing these two enzymes, relative maximal phosphorylation rates (Vm) were eightfold lower for ACV but unchanged for BW B759U. In contrast, the relative rates for deoxycytidine and ara-T were eight- and twofold higher, respectively. The surprisingly good substrate activity with BW B759U compared with that of ACV (Vm/Km' = 0.39 versus 0.01) coincided with susceptibility of the ACV-resistant virus to BW B759U. This clinical variant retained its pathogenicity for mice and was only moderately less neurovirulent than wild-type virus. Although such mutants have the potential to induce illness less responsive to therapy, the recurrence from which the isolate was obtained was typical for this patient in severity and duration. Since this episode, the patient has been treated successfully with ACV.

journal_name

Antimicrob Agents Chemother

journal_title

Antimicrobial agents and chemotherapy

authors

Ellis MN,Keller PM,Fyfe JA,Martin JL,Rooney JF,Straus SE,Lehrman SN,Barry DW

doi

10.1128/aac.31.7.1117

subject

Has Abstract

pub_date

1987-07-01 00:00:00

pages

1117-25

issue

eissn

0066-4804

issn

1098-6596

journal_volume

pub_type

杂志文章

在线工具

Clinical isolate of herpes simplex virus type 2 that induces a thymidine kinase with altered substrate specificity.