Structure of anti-human immunodeficiency virus type 1 antibody 2F5 reported.

2004 DEC 1 - (NewsRx.com & NewsRx.net) -- Researchers report results of a structure and mechanistic analysis of the anti-human immunodeficiency virus type 1 antibody 2F5 in complex with its gp41 epitope in a recent issue of the Journal of Virology.

"The membrane-proximal region of the ectodomain of the gp41 envelope glycoprotein of human immunodeficiency virus type 1 (HIV-1) is the target of three of the five broadly neutralizing anti-HIV-1 antibodies thus far isolated. We have determined crystal structures of the antigen-binding fragment for one of these antibodies, 2F5, in complex with 7-mer, 11-mer, and 17-mer peptides of the gp41 membrane-proximal region, at 2.0-, 2.1-, and 2.24-angstrom resolutions, respectively. The structures reveal an extended gp41 conformation, which stretches over 30 angstroms in length," scientists in the United States report.

"Contacts are made with five complementarity-determining regions of the antibody as well as with nonpolymorphic regions," said Gilad Ofek and colleagues at the National Institute of Allergy and Infectious Diseases. "Only one exclusive charged face of the gp41 epitope is bound by 2F5, while the nonbound face, which is hydrophobic, may be hidden due to occlusion by other portions of the ectodomain. The structures reveal that the 2F5 antibody is uniquely built to bind to an epitope that is proximal to a membrane surface and in a manner mostly unaffected by large-scale steric ...