Characterization of HIV-1 enzyme reverse transcriptase inhibition by the compound 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid through kinetic and in silico studies.
We recently described that the chloroxoquinolinic ribonucleoside 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid (compound A) inhibits the human immunodeficiency virus type 1 (HIV-1) enzyme reverse transcriptase (RT), and its replication in primary cells. Based on these findings, we performed kinetic studies to investigate the mode of inhibition of compound A and its aglycan analog (compound B). We found that both molecules inhibited RT activity independently of the template/primer used. Nevertheless, compound A was 10-fold more potent than compound B. Compound A inhibited the RNA-dependent DNA polymerase (RDDP) activity of RT with an uncompetitive and a noncompetitive mode of action with respect to dTTP incorporation and to template/primer (TP) uptake, respectively. The kinetic pattern of the inhibition displayed by compound A was probably due to its greater affinity for the ternary complex (RT-TP-dNTP) than the enzyme alone or the binary complex (RT-TP). Besides, by means of molecular modeling, we show that compound A bound on the NNRTI binding pocket of RT. However, our molecule targets such a site by making novel interactions with the enzyme RT, when compared to NNRTIs. These include a hydrogen bridge between the 2'-OH of our compound and the Tyr675 of the enzyme RT's chain B. Therefore, compound A is able to synergize with both a NRTI (AZT-TP) and a NNRTI (efavirenz). Taken together, our results suggest that compound A displays a novel mechanism of action, which may be different from classical NRTIs and NNRTIs.
Laboratório de Vírus Respiratórios e do Sarampo, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, RJ, Brazil. tmoreno@ioc.fiocruz.br
Thiago Moreno L
TM
Souza
Diego Q
DQ
Rodrigues
Vitor F
VF
Ferreira
Isakelly Pereira
IP
Marques
Fernanda
F
da Costa Santos
Anna Claudia
AC
Cunha
Maria Cecília Bastos Vieira
MC
de Souza
Izabel Christina
IC
de Palmer Paixão Frugulhetti
Dumith Chequer
DC
Bou-Habib
Carlos Frederico Leite
CF
Fontes
D001665:Binding Sites; D003198:Computer Simulation; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors*; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D011485:Protein Binding; D011804:Quinolines / Q000494:pharmacology*; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D012263:Ribonucleosides / Q000494:pharmacology*
C527872:6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl)quinoline-3-carboxylic acid; D011804:Quinolines; D018894:Reverse Transcriptase Inhibitors; D012263:Ribonucleosides; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase