# Structures and lipid interactions of curvature-inducing membrane peptides by NMR

> **NIH NIH R01** · MASSACHUSETTS INSTITUTE OF TECHNOLOGY · 2020 · $337,339

## Abstract

Project Summary: Enveloped viruses enter cells using their fusion proteins, which merge the virus envelope
and the cell membrane. Determining the atomic-resolution structures and structural evolution of viral fusion
proteins along the fusion pathway is important for understanding how these proteins cause membrane
curvature and dehydration and for developing antiviral drugs to inhibit virus entry. Although crystal
structures of the water-soluble ectodomains of several viral fusion proteins have been determined, much
less is known about the hydrophobic N-terminal fusion peptide (FP) and the C-terminal transmembrane
domain (TMD). In the last funding period, we showed that the FP and TMD of the parainfluenza virus 5
(PIV5) fusion protein, F, adopt membrane-dependent conformations. In phosphatidylethanolamine (PE)-rich
membranes, the β-strand conformation dominates and induces negative Gaussian curvature, which is
characteristic of hemifusion intermediates, to the membrane. This suggests that the β-strand structure is
important for the prefusion to hemifusion transition. Building on these results, we will now determine the
oligomeric structure of the FP and TMD of PIV5 and investigate the structure of the TMD-including region of
the HIV fusion protein, gp41. These experiments will address whether the FP and TMD are trimeric when
they are apart from each other, as in the early fusion stages, and whether they form a trimer of hairpins
when they are brought into close proximity, as in the post-fusion state. In Aim 1, we will measure the
oligomeric structure and intermolecular distances of the PIV5 FP and TMD peptides to probe the early-
fusion structures. 19F and 13C CODEX experiments will be performed to measure intermolecular distances
for both the α-helical and β-sheet conformations of the peptides. These experiments will be done as a
function of membrane composition, and lipid mixtures that mimic the cell membrane and virus envelope will
be used. In Aim 2, we will investigate late-fusion structures of PIV5 by studying a chimera that links the FP
and TMD. Vesicle fusion assays show that the chimera is fusogenic, with lipid mixing activities that are
approximately the sum of the activities of the FP and TMD peptides. We will develop improved 13C and 1H
spin diffusion techniques to measure inter-domain FP-TMD distances as well as intermolecular homo-
oligomeric distances. These distance constraints will test whether a six-helix bundle is formed by the FP
and TMD inside the membrane. In Aim 3, we will extend our structural studies to HIV gp41, focusing on the
antibody-targeted MPER region and the membrane-bound TMD. We will investigate the conformation and
curvature-inducing ability of this domain in lipid membranes, conduct 19F-19F and 13C-19F distance
experiments to measure the relative orientation of the MPER and TMD, their depths of insertion in the
membrane, and the oligomeric structure of this protein. These experiments are expected to provide
fund...

## Key facts

- **NIH application ID:** 9880431
- **Project number:** 5R01GM066976-16
- **Recipient organization:** MASSACHUSETTS INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** Mei Hong
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $337,339
- **Award type:** 5
- **Project period:** 2003-02-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9880431

## Citation

> US National Institutes of Health, RePORTER application 9880431, Structures and lipid interactions of curvature-inducing membrane peptides by NMR (5R01GM066976-16). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9880431. Licensed CC0.

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