HIV entry : a biophysical and mutational analysis of gp41-mediated membrane fusion and its inhibition

The experiments described in this thesis were designed to elucidate the manner in which the HIV-1 envelope protein (Env) initiates infection of host cells, and to develop inhibitors of viral entry. Env comprises two non-covalently attached subunits, gpl20 and gp41, that associate as a trimer on the virion surface. Once gp 120 contacts the target cell, gp41 undergoes extensive conformational changes to mediate fusion of viral and cellular membranes. First, a short hydrophobic stretch of residues at the gp4 1 N-terminus insert into the target membrane, anchoring the protein in both viral and cellular membranes. This 'prehairpin' intermediate structure exposes an N-terminal a-helical coiled coil that is the target of promising antiviral peptides and small molecules. A previously unstudied region of N-terminal trimer was stabilized by fusion to a trimeric scaffold peptide and biophysically characterized (Chapter 2). This hybrid peptide itself potently inhibited HIV fusion, and the basis for this inhibition was assessed by studying mutant molecules. Efforts to use this peptide as an immunogen to elicit anti-gp41 antibodies are also outlined. Similar design strategies may be useful in developing N-terminal peptide inhibitors and HIV vaccine candidates, and in screening for antiviral molecules that bind to this region. As fusion progresses, the prehairpin intermediate resolves into a hairpin structure. This critical transition involves interaction of the N-terminal coiled coil with the gp41 C-terminal region. Evidence suggests that this N-C association provides the energy necessary to promote juxtaposition and merging of viral and cellular membranes.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Biology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Suntoke, Tara R

Advisor dc:contributor.advisor

• Peter S. Kim and David C. Chan.

• Biology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/31181

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/31181