Structural plasticity in I-Ag7 links autoreactivity to hybrid insulin peptides in type I diabetes.
Front Immunol
; 13: 924311, 2022.
Article
em En
| MEDLINE
| ID: mdl-35967292
ABSTRACT
We recently provided evidence for promiscuous recognition of several different hybrid insulin peptides (HIPs) by the highly diabetogenic, I-Ag7-restricted 4.1-T cell receptor (TCR). To understand the structural determinants of this phenomenon, we solved the structure of an agonistic HIP/I-Ag7 complex, both in isolation as well as bound to the 4.1-TCR. We find that HIP promiscuity of the 4.1-TCR is dictated, on the one hand, by an amino acid sequence pattern that ensures I-Ag7 binding and, on the other hand, by the presence of three acidic residues at positions P5, P7 and P8 that favor an optimal engagement by the 4.1-TCR's complementary determining regions. Surprisingly, comparison of the TCR-bound and unbound HIP/I-Ag7 structures reveals that 4.1-TCR binding triggers several novel and unique structural motions in both the I-Ag7 molecule and the peptide that are essential for docking. This observation indicates that the type 1 diabetes-associated I-Ag7 molecule is structurally malleable and that this plasticity allows the recognition of multiple peptides by individual TCRs that would otherwise be unable to do so.
Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Diabetes Mellitus Tipo 1
/
Insulina
Limite:
Humans
Idioma:
En
Revista:
Front Immunol
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Espanha