HIV, retrocyclin, defensin, innate immunity, docking
Retrocyclin RC-101, a θ-defensin with lectin-like properties, potently inhibits infection by many HIV-1 subtypes by binding to the heptad repeat (HR)-2 region of gp41 and preventing six-helix bundle formation. In the present study, we used in silico computational exploration to identify residues of HR2 that interacted with RC-101 and then analyzed the HIV-1 Sequence Database at LANL for residue variations in the HR1 and HR2 segments that could plausibly impart in vivo resistance. Docking RC-101 to gp41 peptides in silico confirmed its strong preference for HR2 over HR1, and implicated residues crucial for its ability to bind HR2. We mutagenized these residues in pseudotyped HIV-1 JR.FL reporter viruses, and subjected them to single round replication assays in the presence of 1.25-10ug/ml RC-101. Except for one mutant that was partially resistant to RC-101, the other pseudotyped viruses with single-site cationic mutations in HR2 manifested absent or impaired infectivity or retained wild-type susceptibility to RC-101. Overall, these data suggest that most mutations capable of rendering HIV-1 resistant to RC-101 will also exert deleterious effects on the ability of HIV-1 to initiate infections - an interesting and novel property for a potential topical microbicide.
Master of Science (M.S.)
Burnett College of Biomedical Sciences
Molecular Biology and Microbiology
Molecular and Microbiology
Length of Campus-only Access
Masters Thesis (Open Access)
Fuhrman, Christopher, "Retrocyclin Rc-101 Overcomes Cationic Mutations On The Heptad Repeat 2 Of Hiv-1 Gp41" (2007). Electronic Theses and Dissertations. 3166.