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Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Poster Abstracts
80
48-POS
Board 48
Antiretroviral Drug Susceptibility of a Hinge Region Variant of HIV-1 Subtype C Protease
Jake Zondagh
, Yasien Sayed.
University of Witwatersrand, Johannesburg, 2050, South Africa.
In South Africa, HIV-1 subtype C (HIV-1 C-SA) is responsible for the majority of HIV
infections. The viability of this virus depends on HIV protease, an enzyme which cleaves
essential viral polyproteins, thereby activating them. Inhibitors targeting this enzyme provide
therapeutic benefits to HIV infected individuals. Unfortunately, inhibitors may become
ineffective over time due to the emergence of drug resistant mutations. In this study, a possible
drug resistant variant of HIV-1 C-SA protease was analysed. The protease variant N37T↑V is
unusual, since it contains an amino acid substitution, as well as an additional amino acid
insertion at the 37th codon. A novel method of purification was developed specifically to
overexpress and purify HIV-1 variant proteases such as N37T↑V. Structural characterisation of
the variant was achieved utilising far-UV circular dichroism, fluorescence spectroscopy and high
performance liquid chromatography. Fluorogenic assays were performed to determine the
catalytic activity of the enzyme. Results indicate that the mutation is structurally non-disruptive.
The N37T↑V protease has a sixfold decrease in fluorogenic substrate processing activity and a
threefold decrease in turnover number compared to the wild-type protease. Moreover, the variant
has a fivefold increase in catalytic efficiency compared to the wild-type protease.