title: Interactions of enantiomers of 2',3'-didehydro-2',3'-dideoxy-fluorocytidine with wild type and M184V mutant HIV-1 reverse transcriptase.
abstract: Both the beta-D-(+) and beta-L-(-)-enantiomers of 2',3'-didehydro-2',3'-dideoxy-5-fluorocytidine (D4FC) are clinically relevant compounds because of their potent anti-HIV and anti-HBV activities. Cross-resistance to L-D4FC with HBV containing a mutation in the conserved polymerase YMDD region has been observed. In order to better understand the effects of stereochemistry on planar 5-fluorinated cytidine analogs and to gain insight into resistance caused by YMDD mutations in HIV-1 reverse transcriptase (RT), a combination of transient kinetic studies and computer modeling were employed. In contrast to studies with the (+) and (-) isomers of 3TC-TP and FTC-TP, it was found that wild type RT had a high enantiomeric selectivity between the D-(+) and L-(-) isomers of D4FC-TP. While no resistance was conferred by the methionine 184 to valine mutation to D-D4FC-TP, L-D4FC-TP was incorporated 50- to 70-fold less efficiently. The kinetic parameters of incorporation in the presence of L-D4FC-TP by RT(WT) and the mechanism of resistance by RT(M184V) were found to be distinct from those seen with the corresponding L-isomers containing an oxathiolane ring: (-)-3TC-TP and (-)-FTC-TP. Molecular modeling suggests that L- and D-D4FC-TP are positioned in the active site favorably for incorporation by RT(WT) and that L-D4FC-TP, but not D-D4FC-TP, is sterically hindered by the addition of a beta branched amino acid at position 184 of RT(M184V).
authors.affiliation: Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8066, USA.
authors.forename: Adrian S
authors.initials: AS
authors.lastname: Ray
authors.forename: Eisuke
authors.initials: E
authors.lastname: Murakami
authors.forename: Celeste N
authors.initials: CN
authors.lastname: Peterson
authors.forename: Junxing
authors.initials: J
authors.lastname: Shi
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Schinazi
authors.forename: Karen S
authors.initials: KS
authors.lastname: Anderson
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D003570:Cytidine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D003845:Deoxycytosine Nucleotides / Q000378:metabolism / Q000494:pharmacology; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017354:Point Mutation; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D013237:Stereoisomerism; D016047:Zalcitabine / Q000031:analogs & derivatives
chemical_list: D003845:Deoxycytosine Nucleotides; D018894:Reverse Transcriptase Inhibitors; C024107:2'-deoxycytidine 5'-triphosphate; D003570:Cytidine Triphosphate; D016047:Zalcitabine; D054303:HIV Reverse Transcriptase; C099405:dexelvucitabine