Kinetic and thermodynamic characterisation of HIV-protease inhibitors against E35D↑G↑S mutant in the South African HIV-1 subtype C protease

Sibusiso Maseko,Eden Padayachee,Siyabonga Maphumulo,Thavendran Govender,Yasien Sayed,Glenn Maguire,Johnson Lin,Tricia Naicker,Sooraj Baijnath,Kruger Hendrik Gerhardus

doi:10.1080/14756366.2019.1636234

Sibusiso Maseko, Eden Padayachee + Show 8 more

Open Access

https://doi.org/10.1080/14756366.2019.1636234

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Abstract

Herein, we report the effect of nine FDA approved protease inhibitor drugs against a new HIV-1 subtype C mutant protease, E35D↑G↑S. The mutant has five mutations, E35D, two insertions, position 36 (G and S), and D60E. Kinetics, inhibition constants, vitality, Gibbs free binding energies are reported. The variant showed a decreased affinity for substrate and low catalytic efficiency compared to the wild type. There was a significant decrease in the binding of seven FDA approved protease inhibitors against the mutant (p < .0001). Amprenavir and ritonavir showed the least decrease, but still significant reduced activity in comparison to the wildtype (4 and 5 folds, respectively, p = .0021 and .003, respectively). Nelfinavir and atazanavir were the worst inhibitors against the variant as seen from the IC50, with values of 1401 ± 3.0 and 685 ± 3.0 nM, respectively. Thermodynamics data showed less favourable Gibbs free binding energies for the protease inhibitors to the mutant.

Highlights

The human immunodeficiency virus (HIV) is a retrovirus from the Retroviride family and is responsible for acquired immune deficiency syndrome (AIDS), which was first reported in 19811
C-SA HIV protease and mutant E35D"G"S were cloned in pGEX6P-1 and expressed in Escherichia coli BL21 (DE3) pLysS
The lower Km for the wild type means that the wildtype exhibited a higher affinity for the substrate than the mutant

Summary

Introduction

The human immunodeficiency virus (HIV) is a retrovirus from the Retroviride family and is responsible for acquired immune deficiency syndrome (AIDS), which was first reported in 19811. This infection is controlled by the use of antiviral drugs which helps reduce the mortality and morbidity as well as promote increased patient life expectancy[2]. There are currently nine FDA approved protease inhibitors[7], originally designed for type B HIV PR8 These inhibitors represent the most potent anti-AIDS drug reported to date and are essential components of the highly active antiretroviral therapy (HAART)[9]. HAART is credited with significantly lowering AIDSrelated deaths, and is currently implemented to the whole world as the standard care for HIV-AIDS treatment[9]

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