An Insertion Mutation That Distorts Antibody Binding Site Architecture Enhances Function of a Human Antibody
| Autor: | Ian A. Wilson, Patricia B. Smith, Damian C. Ekiert, Jens C. Krause, Terrence M. Tumpey, James E. Crowe |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Protein Conformation
Molecular Sequence Data Immunoglobulin Variable Region Gene mutation Antibodies Viral medicine.disease_cause Microbiology Cell Line Mice 03 medical and health sciences Influenza A Virus H1N1 Subtype 0302 clinical medicine Virology Influenza Human Gene duplication Influenza A virus medicine Animals Humans Insertion Binding site Polymerase 030304 developmental biology Mice Inbred BALB C 0303 health sciences Base Sequence biology Point mutation Antibodies Monoclonal Molecular biology QR1-502 3. Good health Mutagenesis Insertional biology.protein Immunoglobulin heavy chain Female Binding Sites Antibody Immunoglobulin Heavy Chains Research Article Protein Binding 030215 immunology |
| Zdroj: | mBio mBio, Vol 2, Iss 1 (2011) |
| ISSN: | 2150-7511 2161-2129 |
| Popis: | The structural and functional significance of somatic insertions and deletions in antibody chains is unclear. Here, we demonstrate that a naturally occurring three-amino-acid insertion within the influenza virus-specific human monoclonal antibody 2D1 heavy-chain variable region reconfigures the antibody-combining site and contributes to its high potency against the 1918 and 2009 pandemic H1N1 influenza viruses. The insertion arose through a series of events, including a somatic point mutation in a predicted hot-spot motif, introduction of a new hot-spot motif, a molecular duplication due to polymerase slippage, a deletion due to misalignment, and additional somatic point mutations. Atomic resolution structures of the wild-type antibody and a variant in which the insertion was removed revealed that the three-amino-acid insertion near the base of heavy-chain complementarity-determining region (CDR) H2 resulted in a bulge in that loop. This enlarged CDR H2 loop impinges on adjacent regions, causing distortion of the CDR H1 architecture and its displacement away from the antigen-combining site. Removal of the insertion restores the canonical structure of CDR H1 and CDR H2, but binding, neutralization activity, and in vivo activity were reduced markedly because of steric conflict of CDR H1 with the hemagglutinin antigen. IMPORTANCE Antibody diversification through VDJ gene recombination, junctional variation, and somatic hypermutation has clear importance for the generation of mature, high-affinity antibodies. Between 1.3 and 6.5% of antibody variable gene sequences have been reported to contain insertions or deletions, but their structural and functional significance remains less well defined. The pandemic influenza virus hemagglutinin antibody 2D1 data suggest that somatic insertions and deletions in antibody genes contribute important structural and functional features. We predict that such features can be critical for affinity and functional maturation of the human antibody repertoire. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|