Structural Analysis of Human and Macaque mAbs 2909 and 2.5B: Implications for the Configuration of the Quaternary Neutralizing Epitope of HIV-1 gp120.
Spurrier, B., Sampson, J.M., Totrov, M., Li, H., O'Neal, T., Williams, C., Robinson, J., Gorny, M.K., Zolla-Pazner, S., Kong, X.P.(2011) Structure 19: 691-699
- PubMed: 21565703 
- DOI: https://doi.org/10.1016/j.str.2011.02.012
- Primary Citation of Related Structures:  
3Q6F, 3Q6G - PubMed Abstract: 
The quaternary neutralizing epitope (QNE) of HIV-1 gp120 is preferentially expressed on the trimeric envelope spikes of intact HIV virions, and QNE-specific monoclonal antibodies (mAbs) potently neutralize HIV-1. Here, we present the crystal structures of the Fabs of human mAb 2909 and macaque mAb 2.5B. Both mAbs have long beta hairpin CDR H3 regions >20 Å in length that are each situated at the center of their respective antigen-binding sites. Computational analysis showed that the paratopes include the whole CDR H3, while additional CDR residues form shallow binding pockets. Structural modeling suggests a way to understand the configuration of QNEs and the antigen-antibody interaction for QNE mAbs. Our data will be useful in designing immunogens that may elicit potent neutralizing QNE Abs.
Organizational Affiliation: 
Department of Biochemistry, NYU School of Medicine, New York, NY 10016, USA.