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Publication Abstract from PubMed

Variable regions 1 and 2 (V1/V2) of human immunodeficiency virus-1 (HIV-1) gp120 envelope glycoprotein are critical for viral evasion of antibody neutralization, and are themselves protected by extraordinary sequence diversity and N-linked glycosylation. Human antibodies such as PG9 nonetheless engage V1/V2 and neutralize 80% of HIV-1 isolates. Here we report the structure of V1/V2 in complex with PG9. V1/V2 forms a four-stranded beta-sheet domain, in which sequence diversity and glycosylation are largely segregated to strand-connecting loops. PG9 recognition involves electrostatic, sequence-independent and glycan interactions: the latter account for over half the interactive surface but are of sufficiently weak affinity to avoid autoreactivity. The structures of V1/V2-directed antibodies CH04 and PGT145 indicate that they share a common mode of glycan penetration by extended anionic loops. In addition to structurally defining V1/V2, the results thus identify a paradigm of antibody recognition for highly glycosylated antigens, which-with PG9-involves a site of vulnerability comprising just two glycans and a strand.

Structure of HIV-1 gp120 V1/V2 domain with broadly neutralizing antibody PG9.,McLellan JS, Pancera M, Carrico C, Gorman J, Julien JP, Khayat R, Louder R, Pejchal R, Sastry M, Dai K, O'Dell S, Patel N, Shahzad-Ul-Hussan S, Yang Y, Zhang B, Zhou T, Zhu J, Boyington JC, Chuang GY, Diwanji D, Georgiev I, Do Kwon Y, Lee D, Louder MK, Moquin S, Schmidt SD, Yang ZY, Bonsignori M, Crump JA, Kapiga SH, Sam NE, Haynes BF, Burton DR, Koff WC, Walker LM, Phogat S, Wyatt R, Orwenyo J, Wang LX, Arthos J, Bewley CA, Mascola JR, Nabel GJ, Schief WR, Ward AB, Wilson IA, Kwong PD Nature. 2011 Nov 23. doi: 10.1038/nature10696. PMID:22113616^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.