An anti-HER2 nanobody binds to its antigen HER2 via two independent paratopes.
Int J Biol Macromol
; 182: 502-511, 2021 Jul 01.
Article
em En
| MEDLINE
| ID: mdl-33848543
ABSTRACT
High-resolution structural data of complexes between antibodies and membrane receptors still represent a demanding task. In this study, we used complementary sets of experimental data to obtain a structural model of the complex formed by the human epidermal growth factor receptor 2 (HER2) and its specific nanobody A10. First we identified by NMR the residues that bind or rearrange as a consequence of the complex formation. In parallel, the complex was cross-linked, digested and the resulting peptides were characterized by mass-spectrometry to define maximal distance restraints between HER2 and A10 amino acids in their complex. These independent datasets guided a docking process, refined by molecular dynamics simulations, to develop a model of the complex and estimate per-residue free-energy contributions. Such a model explains the experimental data and identifies a second, non-canonical paratope, located in the region opposite to the conventional nanobody paratope, formed by the hypervariable loop regions LH1 and LH3. Both paratopes contributed substantially to the overall affinity by binding to independent HER2 epitopes. Nanobody mutants with substitution of key interaction residues, as indicated by the model, possess significantly lower affinity for HER2. This is the first described case of a "natural" biparatopic nanobody, directly selected by in-vitro panning.
Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Sítios de Ligação de Anticorpos
/
Receptor ErbB-2
/
Anticorpos de Cadeia Única
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Int J Biol Macromol
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Alemanha