Structural basis of clade‐specific HIV‐1 neutralization by humanized anti‐V3 monoclonal antibody KD‐247. Issue 1 (28th October 2014)

• Record Type: Journal Article
• Authors: Kirby, Karen A.; Ong, Yee Tsuey; Hachiya, Atsuko; Laughlin, Thomas G.; Chiang, Leslie A.; Pan, Yun; Moran, Jennifer L.; Marchand, Bruno; Singh, Kamalendra; Gallazzi, Fabio; Quinn, Thomas P.; Yoshimura, Kazuhisa; Murakami, Toshio; Matsushita, Shuzo; Sarafianos, Stefan G.
• Is Part Of: FASEB journal. Volume 29:Issue 1(2015)
• Page Start: 70
• Page End: 80
• Publication Date: 2014-10-28
• Subjects: crystal structure -- entry -- HIV -- single‐chain variable fragment; Biology -- Periodicals; Biology, Experimental -- Periodicals; 570
• DOI: 10.1096/fj.14-252262
• Languages: English
• ISSNs: 0892-6638

Abstract

Abstract : Humanized monoclonal antibody KD‐247 targets the Gly 312 ‐Pro 313 ‐Gly 314 ‐Arg 315 arch of the third hypervariable (V3) loop of the HIV‐1 surface glycoprotein. It potently neutralizes many HIV‐1 clade B isolates, but not of other clades. To understand the molecular basis of this specificity, we solved a high‐resolution (1.55 Å) crystal structure of the KD‐247 antigen binding fragment and examined the potential interactions with various V3 loop targets. Unlike most antibodies, KD‐247 appears to interact with its target primarily through light chain residues. Several of these interactions involve Arg 315 of the V3 loop. To evaluate the role of light chain residues in the recognition of the V3 loop, we generated 20 variants of KD‐247 single‐chain variable fragments with mutations in the antigen‐binding site. Purified proteins were assessed for V3 loop binding using Alpha‐Screen technology and for HIV‐1 neutralization. Our data revealed that recognition of the clade‐specificity defining residue Arg 315 of the V3 loop is based on a network of interactions that involve Tyr L32, Tyr L92, and Asn L27d that directly interact with Arg 315, thus elucidating the molecular interactions of KD‐247 with its V3 loop target—Kirby, K. A., Ong, Y. T., Hachiya, A., Laughlin, T. G., Chiang, L. A., Pan, Y., Moran, J. L., Marchand, B., Singh, K., Gallazzi, F., Quinn, T. P., Yoshimura, K., Murakami, T., Matsushita, S., Sarafianos, S. G., Structural basis of clade‐specific HIV‐1 neutralization by humanized anti‐V3 monoclonal antibody KD‐247. FASEB J. 29, 70–80 (2015). www.fasebj.org