RT Journal Article
SR Electronic
T1 The Role of Thr139 in the Human Immunodeficiency Virus Type 1 Reverse Transcriptase Sensitivity to (+)-Calanolide A
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 652
OP 659
DO 10.1124/mol.105.012351
VO 68
IS 3
A1 Auwerx, Joeri
A1 Rodríguez-Barrios, Fátima
A1 Ceccherini-Silberstein, Francesca
A1 San-Félix, Ana
A1 Velázquez, Sonsoles
A1 De Clercq, Erik
A1 Camarasa, María-José
A1 Perno, Carlo-Federico
A1 Gago, Federico
A1 Balzarini, Jan
YR 2005
UL http://molpharm.aspetjournals.org/content/68/3/652.abstract
AB The coumarins represent a unique class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) that were isolated from tropical plants. (+)-Calanolide A, the most potent compound of this class, selects for the T139I resistance mutation in HIV-1 reverse transcriptase (RT). Seven RTs mutated at amino acid position 139 (Ala, Lys, Tyr, Asp, Ile, Ser, and Gln) were constructed by site-directed mutagenesis. The mutant T139Q enzyme retained full catalytic activity compared with wild-type RT, whereas the mutant T139I, T139S, and T139A RTs retained only 85 to 50% of the activity. Mutant T139K, T139D, and T139Y RTs had seriously impaired catalytic activities. The mutations in the T139I and T139D RTs were shown to destabilize the RT heterodimer. (+)-Calanolide A lost inhibitory activity (up to 20-fold) against the mutant T139Y, T139Q, T139K, and T139I enzymes. All of the mutant enzymes retained marked susceptibility toward the other NNRTIs, including nevirapine, delavirdine, efavirenz, thiocarboxanilide UC-781, quinoxaline GW867420X, TSAO [[2′,5′-bis-O-(tert-butyldimethylsilyl)-β-d-ribofuranosyl]-3′-spiro-5″-(4″-amino-1″,2″-oxathiole-2″,2″-dioxide)] derivatives, and the nucleoside inhibitor, ddGTP. The fact that the T139I RT 1) proved to be resistant to (+)-calanolide A, 2) represents a catalytically efficient enzyme, and 3) requires only a single transition point mutation (ACA→ATA) in codon 139 seems to explain why mutant T139I RT virus strains, but not virus strains containing other amino acid changes at this position, predominantly emerge in cell cultures under (+)-calanolide A pressure.