Problems of drug resistance, latent viral reservoirs, and the toxic effects of current anti-HIV drugs call for the development of new anti-retrovirals with different modes of action. A promising approach for drug development is interference with the entry of HIV into cells. HIV entry is a complex process that requires binding of the HIV envelope protein gp120 to a cellular co-receptor (CCR5 or CXCR4). This proposal seeks to enhance understanding of the structure of CCR5 and CXCR4, including the amino acid residues that contribute to alternative modes of antagonist binding and contact residues involved in agonist activation. Virus isolates that require CCR5 for entry are the predominant infectious forms of HIV transmitted from one person to another. Virus strains that require CXCR4 for entry often emerge in the late stages of infection, are considered to be more pathogentic, and correlate with severe loss of CD4+ T lymphocytes and the development of opportunistic infections due to severe immunodeficiency. Several small-molecule antagonists for CCR5 or CXCR4 that block virus infection have been identified as promising drug leads by pharmaceutical companies, but their binding sites on the receptors and the mechanism of HIV blocking are poorly understood. This project will use high-affinity photoactive analogs of antagonist and agonist molecules to examine the interaction sites in CCR5 and CXCR4-and will investigate the roles of the residues at the crosslinking sites by site-specific mutagenesis. We will also investigate the changes in the conformation of CCR5 that result in activation or antagonism of HIV binding, by studying the interaction sites of monoclonal antibodies specific for the antagonist- or agonist-bound conformations of CCR5. The proposed studies will lead to a better understanding of the structure and function of CCR5 and CXCR4 and aim to provide information useful for the design of more potent drugs that inhibit HIV entry while minimizing side effects due to activating or blocking normal functions of CCR5 and CXCR4.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI064107-01A1
Application #
6947466
Study Section
AIDS Discovery and Development of Therapeutics Study Section (ADDT)
Program Officer
Ussery, Michael A
Project Start
2005-02-01
Project End
2010-01-31
Budget Start
2005-02-01
Budget End
2006-01-31
Support Year
1
Fiscal Year
2005
Total Cost
$353,750
Indirect Cost
Name
Montana State University - Bozeman
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
625447982
City
Bozeman
State
MT
Country
United States
Zip Code
59717
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