Author:
Huan Xuelu,Zhuo Nicole,Lee Haur Yueh,Ren Ee Chee
Abstract
AbstractAllopurinol, widely used in gout treatment, is the most common cause of severe cutaneous adverse drug reactions. The risk of developing such life-threatening reactions is increased particularly for HLA-B*58:01 positive individuals. However the mechanism of action between allopurinol and HLA remains unknown. We demonstrate here that a Lamin A/C peptide KAGQVVTI which is unable to bind HLA-B*58:01 on its own, is enabled to form a stable peptide-HLA complex only in the presence of allopurinol. Crystal structure analysis reveal that allopurinol non-covalently facilitated KAGQVVTI to adopt an unusual binding conformation, whereby the C-terminal isoleucine does not engage as a PΩ that typically fit deeply in the binding F-pocket. A similar observation, though to a lesser degree was seen with oxypurinol. Presentation of unconventional peptides by HLA-B*58:01 aided by allopurinol contributes to our fundamental understanding of drug-HLA interactions. The binding of peptides from endogenously available proteins such as self-protein lamin A/C and viral protein EBNA3B suggest that aberrant loading of unconventional peptides in the presence of allopurinol or oxypurinol may be able to trigger anti-self reactions that can lead to Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).
Publisher
Springer Science and Business Media LLC