Proline Is Not Uniquely Capable of Providing the Pivot Point for Domain Swapping in 2G12, a Broadly Neutralizing Antibody against HIV-1

Johannes S Gach,Paul G Furtmüller,Heribert Quendler,Paul Messner,Ralf Wagner,Hermann Katinger,Renate Kunert

doi:10.1074/jbc.m109.058792

Abstract

The human monoclonal antibody 2G12 is a member of a small group of broadly neutralizing antibodies against human immunodeficiency virus type 1. 2G12 adopts a unique variable heavy domain-exchanged dimeric configuration that results in an extensive multivalent binding surface and the ability to bind with high affinity to densely clustered high mannose oligosaccharides on the "silent" face of the gp120 envelope glycoprotein. Here, we further define the amino acids responsible for this extraordinary domain-swapping event in 2G12.

Highlights

Austrian Science Fund J2845-B13. □S The on-line version of this article contains supplemental Figs
We discovered that the domain exchange-enabling properties of ProH113 at the elbow region of 2G12 can be emulated by other residues
2G12-JH3, the J region of 2G12 mutants with that of wild-type 2G12 (2G12-wt) was replaced by a corresponding germ line region IGHJ3*01, resulting in five amino acid substitutions and one deletion (Fig. 1B). Two of these substitutions and the amino acid deletion occur in the complementarity-determining region (CDR) 3, whereas the remaining three substitutions are located in the J region

Summary

Introduction

Austrian Science Fund J2845-B13. □S The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. We have generated three IgG1 2G12 heavy chain mutants based on the Fab 2G12 crystal structure and tested Our results support a combination of up to four somatic mutations at the VH/VHЈ interface and elbow region as being responsible for promoting domain exchange in 2G12.

Results

Conclusion