title: N2-Phenyl-9-(hydroxyalkyl)guanines and related compounds are substrates for Herpes simplex virus thymidine kinases.
abstract: Herpes simplex virus (HSV) types 1 and 2 thymidine kinases (TK) are responsible for phosphorylation of antiherpes acyclonucleosides such as acyclovir (ACV) and 9-(4-hydroxybutyl)guanine (HBG). Related compounds, the N2-phenyl-9-(hydroxyalkyl)guanines, are devoid of direct antiviral activity, but potently inhibit the viral TKs and block viral reactivation from latencyin vivo. The similarity in structure between the acyclonucleosides and TK inhibitors raised the question of the relevance of phosphorylation of certain of the latter analogs in their mechanisms of action. Using recombinant TKs and HPLC analysis of reaction mixtures, we report that the lead TK inhibitor N2-phenyl-9 -(4-hydroxybutyl)guanine (HBPG) and its pentyl homolog (HPnPG) are excellent substrates for the enzymes, approaching the efficiency with which the natural substrate thymidine is phosphorylated, and significantly better than ACV or HBG. Other 9-hydroxyalkyl congeners are substrates for the enzymes, but with much poorer efficiency. HBPG triphosphate was a poor inhibitor of HSV DNA polymerase, the target of acyclonucleoside triphosphates, suggesting that phosphorylation of HBPG is not important in its mechanism of blocking viral reactivationin vivo. The fact that HBPG is an efficient substrate is consistent, however, with its binding mode based both on molecular modeling studies and x-ray structure of the HBPG:TK complex.
authors.affiliation: Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy 27100.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lossani
authors.affiliation: Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy 27100.
authors.forename: Lida
authors.initials: L
authors.lastname: Savi
authors.affiliation: GLSynthesis Inc., One Innovation Drive, Worcester, MA 01605.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Manikowski
authors.affiliation: GLSynthesis Inc., One Innovation Drive, Worcester, MA 01605.
authors.forename: Andrew
authors.initials: A
authors.lastname: Maioli
authors.affiliation: GLSynthesis Inc., One Innovation Drive, Worcester, MA 01605.
authors.forename: Joseph
authors.initials: J
authors.lastname: Gambino
authors.affiliation: Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy 27100.
authors.forename: Federico
authors.initials: F
authors.lastname: Focher
authors.affiliation: Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy 27100.
authors.forename: Silvio
authors.initials: S
authors.lastname: Spadari
authors.affiliation: GLSynthesis Inc., One Innovation Drive, Worcester, MA 01605.
authors.forename: George E
authors.initials: GE
authors.lastname: Wright
references.citation: J Virol. 1979 Oct;32(1):72-7
references.pmid: 232189
references.citation: Biochem Pharmacol. 1981 Nov 15;30(22):3071-7
references.pmid: 6279102
references.citation: Bioconjug Chem. 2002 Mar-Apr;13(2):309-16
references.pmid: 11906269
references.citation: J Biol Chem. 1989 May 5;264(13):7405-11
references.pmid: 2540193
references.citation: J Med Chem. 1990 Jan;33(1):203-6
references.pmid: 2153203
references.citation: Antiviral Res. 1983 Aug;3(2):77-86
references.pmid: 6312878
references.citation: Antiviral Res. 1996 May;30(2-3):87-94
references.pmid: 8783801
references.citation: Chromosoma. 1992;102(1 Suppl):S67-71
references.pmid: 1337882
references.citation: J Med Chem. 1988 Aug;31(8):1496-500
references.pmid: 2840499
references.citation: J Med Chem. 2005 Jun 2;48(11):3919-29
references.pmid: 15916444
references.citation: FEBS Lett. 1999 Jan 25;443(2):121-5
references.pmid: 9989588