Molecular insights into the mechanisms of HIV-1 reverse transcriptase resistance to nucleoside analogs

The causative agent of acquired immunodeficiency syndrome, HIV-1, depends on one of its enzymes, reverse transcriptase, to copy its single stranded RNA genome into a double stranded DNA nucleic acid suitable for integration in the host cell genome. In the last two decades, the advances in the knowledge of the kinetic mechanism of reverse transcription and in the determination of the crystallographic structures for the complexes of the enzyme with substrates and products were huge. However, all of this knowledge resulted in the design of RT inhibitors for which the virus, after a short period of exposure, becomes less susceptible, due to the development of resistance. The development of resistance is caused by the high frequency of viral mutation and the toxicity of those same drugs. Therefore, a closer look at all the available information might shed some light into this subject and help to develop new strategies to overcome the lack of long term clinical efficiency of these drugs. Here, we present a critical atomic level study of all the mutations that have been detected and reported so far, as a reaction of the enzyme to counteract the action of the inhibitors.