Open AccessViral Evolution in Response to the Broad-Based Retroviral Protease Inhibitor TL-3
Author(s) -
Bernd Bühler,
YingChuan Lin,
Garrett M. Morris,
Arthur J. Olson,
ChiHuey Wong,
Douglas D. Richman,
John H. Elder,
Bruce E. Torbett
Publication year - 2001
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.75.19.9502-9508.2001
Subject(s) - protease , biology , ns2 3 protease , virus , viral replication , virology , mutant , enzyme , protease inhibitor (pharmacology) , in vitro , wild type , hiv 1 protease , feline immunodeficiency virus , microbiology and biotechnology , lentivirus , biochemistry , gene , viral load , viral disease , antiretroviral therapy
TL-3 is a protease inhibitor developed using the feline immunodeficiency virus protease as a model. It has been shown to efficiently inhibit replication of human, simian, and feline immunodeficiency viruses and therefore has broad-based activity. We now demonstrate that TL-3 efficiently inhibits the replication of 6 of 12 isolates with confirmed resistance mutations to known protease inhibitors. To dissect the spectrum of molecular changes in protease and viral properties associated with resistance to TL-3, a panel of chronological in vitro escape variants was generated. We have virologically and biochemically characterized mutants with one (V82A), three (M46I/F53L/V82A), or six (L24I/M46I/F53L/L63P/V77I/V82A) changes in the protease and structurally modeled the protease mutant containing six changes. Virus containing six changes was found to be 17-fold more resistant to TL-3 in cell culture than was wild-type virus but maintained similar in vitro replication kinetics compared to the wild-type virus. Analyses of enzyme activity of protease variants with one, three, and six changes indicated that these enzymes, compared to wild-type protease, retained 40, 47, and 61% activity, respectively. These results suggest that deficient protease enzymatic activity is sufficient for function, and the observed protease restoration might imply a selective advantage, at least in vitro, for increased protease activity.