# Mechanisms of retroviral integrase-DNA complexes assembly

> **NIH NIH R21** · SAINT LOUIS UNIVERSITY · 2022 · $189,375

## Abstract

Abstract
 Retrovirus integrase (IN) is responsible for integration of viral genome into host DNA.
IN multimerizes on viral DNA to produce intasomes. Intasomes produced from
lentiviruses including HIV-1 demonstrate an extended architecture compared to other
retroviral intasomes. The specific aims of this proposal are to: 1) determine the structure
of HIV-2 intasomes by single-particle cryo-electron microscopy (cryo-EM) in the presence
of HIV-1 IN strand transfer inhibitors (INSTIs); 2) determine the mechanisms of assembly
of extended intasome architectures using HIV-1 and HIV-2 as model systems; and 3)
produce and determine the structure of intasomes assembled with untagged native
tetrameric HIV-1 and dimeric HIV-2 IN, as fusion tags used to enhance IN solubility may
interfere with positioning of IN subunits in intasomes.
 As proof of concept and to demonstrate expertise, we determined the structure of
Rous sarcoma virus octameric (8 IN subunits) cleaved synaptic complex intasome
stabilized with INSTI MK-2048 at 3.21Å resolution by cryo-EM. We have obtained
preliminary data for HIV-1 and HIV-2 intasomes structures using cryo-EM.
 The partial intasome structures from other research groups have further determined
the mechanisms of HIV-1 INSTIs. However, the distal subunits which are crucial for
intasome assembly and catalysis are not resolved in these structures. We will use wt HIV-
1 and HIV-2 IN with native N-terminal residue phenylalanine to produce intasomes for
their complete structure determination by cryo-EM. HIV-2 is a significant human pathogen
and determining of the structure of HIV-2 intasome with INTSIs will be complementary
and confirmatory for HIV-1 studies. These studies will provide a greater understanding of
intasome assembly mechanisms and facilitate development of active site and novel
allosteric IN inhibitors.

## Key facts

- **NIH application ID:** 10472029
- **Project number:** 5R21AI165081-02
- **Recipient organization:** SAINT LOUIS UNIVERSITY
- **Principal Investigator:** Krishan Kumar Pandey
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $189,375
- **Award type:** 5
- **Project period:** 2021-08-19 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10472029

## Citation

> US National Institutes of Health, RePORTER application 10472029, Mechanisms of retroviral integrase-DNA complexes assembly (5R21AI165081-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10472029. Licensed CC0.

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