Isolation and Characterization of Aptamers Targeted to Inhibit HIV Protease Matur

Colorado State University, Fort Collins CO

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Abstract

DESCRIPTION (provided by applicant): HIV protease is a well established target for the inhibition of viral replication and there are a handful of FDA- approved drugs that are being used to weigh down HIV protease activity. However, these drugs are exclusively targeted to the catalytic site of HIV protease and constant emergence of drug-resistant strains in patients under the therapy underscores the urgent need for the discovery and development of therapeutics with novel mechanisms of action. Here, we seek to explore an unconventional approach that is aimed to interfere with protease maturation, a viral specific autoprocessing reaction responsible for the production of active protease. In the infected cell, HIV protease is initially translated as part of the Gag-Pol precursor. This embedded immature protease has intrinsic but very limited activity and the full proteolytic activity is only associated with the mature protease after it is released from the precursor. Extensive research has established that mature protease exists as stable dimers while protease precursors are predominantly monomer, and that precursor dimerization coupled with the cleavages releasing the amino terminus is critical for protease maturation. We recently discovered that changing a positively charged surface residue (H69) to negatively charged amino acids also abolished protease maturation in E. coli and transfected mammalian cells. Therefore, I hypothesize that masking the precursor at regions that are critical for the autoprocessing reaction through the use of high affinity molecules would interfere with protease maturation and inhibit the production of fully active protease. In order to test the feasibility of this concept, we plan to isolate RNA aptamers specific to the protease precursor (Aim 1). Among these, high affinity (Kd <1 <M) aptamers will be further evaluated in order to identify candidate aptamers that interfere with protease maturation in vitro and in transfected cells (Aim 2). PUBLIC HEALTH RELEVANCE: Protease maturation is a virus specific process that is responsible for the production of active HIV protease, an indispensable enzyme that is absolutely required for HIV replication. Currently, there is no drug that is targeted to block or inhibit this process. Our goal here is to establish an effective way to interfere with protease maturation for the development of novel anti-HIV medicines.