# Structural Basis of Activity of and Resistance to HIV Integrase Inhibitors

## TL;DR

This paper explores how HIV becomes resistant to a key class of drugs and suggests ways to improve future treatments.

## Contribution

The study combines structural biology and other methods to uncover resistance mechanisms and guide drug improvement.

## Key findings

- Drug-resistant mutations in HIV integrase are linked to specific structural changes observed via cryo-EM.
- Novel resistance pathways are identified that could inform the design of more effective INSTIs.
- Collaboration with chemists is leading to the development of therapeutics targeting resistant HIV strains.

## Abstract

The Human Immunodeficiency Virus Type 1 (HIV) currently infects ∼40 million people worldwide. In the absence of a cure, antiretroviral therapy represents the primary treatment option, because it slows disease progression and reduces new infections. Integrase (IN) Strand Transfer Inhibitors (INSTIs) are a class of antiretroviral therapeutics that block integration of viral DNA into host chromosomes. This process is mediated by the viral IN enzyme, which assembles into oligomeric nucleoprotein complexes on the ends of viral DNA, termed “intasomes”. INSTIs selectively target intasomes and represent first-line therapies in the clinic. However, the emergence of IN variants resistant to INSTIs is becoming a greater clinical problem. We are using interdisciplinary approaches that include structural biology via cryogenic electron microscopy, biochemistry, cellular virology, and computation to provide a mechanistic understanding of both how and why select drug resistant mutations arise in response to leading clinically used drugs, identify and analyze novel pathways of drug resistance, and devise strategies to predict how resistant mutations emerge. We are also working with chemists who are developing more potent therapeutics that aim to be effective against drug resistant viruses. Our work aims to improve our understanding of an important class of drugs used to treat people living with HIV, identify mechanisms, pathways, and patterns of clinically relevant resistance to INSTIs, and provide specific guidelines for their rational improvement, under a broader umbrella of “personalized medicine”.