# Structure-function studies of the membrane-interacting domains of HIV-1 Env spike

> **NIH NIH R01** · BOSTON CHILDREN'S HOSPITAL · 2024 · $199,874

## Abstract

Project Summary
Viral fusion proteins are fascinating protein folding machineries capable of adopting completely different
conformations during the fusion process; they are also important vaccine and therapeutic targets. Previous
studies have revealed both pre- and post-fusion conformations of the soluble fragments of many viral fusion
proteins, but less is known for structures of their fusion peptide, transmembrane (TM) and membrane-proximal
regions in the context of lipid bilayers. We hypothesize that membrane-interacting regions of other fusion proteins
related to HIV-1 envelope protein (Env) adopt defined oligomeric structures that are critical for the stability,
function and antigenicity of the full-length proteins in membrane. We have previously determined the structures
of the TM, membrane proximal external region, and cytoplasmic tail of HIV-1 Env in bicelles that mimic lipid
bilayers using the latest NMR technology. We find that these regions all form well-ordered trimeric clusters and
are conformationally coupled, and that disrupting them can reduce fusion and alter the antigenic structure of the
entire Env. In the current project, we propose to apply our NMR/bicelle technology to investigate the membrane
regions of SIV Env and the recently emerged SARS-CoV-2 spike (S), and to use cryo-electron microscopy to
determine structures of the full-length proteins reconstituted in lipid nanodiscs. We will define roles in membrane
fusion of critical structural elements of these regions by deep mutagenesis and functional assays. We will pursue
the following specific aims: 1) we will investigate the membrane-interacting components of SIV Env; 2) we will
investigate the membrane-interacting components in the postfusion arrangement; 3) we will determine structures
of the full-length SIV Env and SARS-CoV-2 S in the context of membrane; 4) we will elucidate roles of the
membrane-interacting domains of HIV/SIV Env and SARS-CoV-2 S in their stability, function and antigenicity.

## Key facts

- **NIH application ID:** 11078449
- **Project number:** 3R01AI127193-09S1
- **Recipient organization:** BOSTON CHILDREN'S HOSPITAL
- **Principal Investigator:** Bing Chen
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $199,874
- **Award type:** 3
- **Project period:** 2016-05-20 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11078449

## Citation

> US National Institutes of Health, RePORTER application 11078449, Structure-function studies of the membrane-interacting domains of HIV-1 Env spike (3R01AI127193-09S1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/11078449. Licensed CC0.

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