Crystal structure of a TAPBPR-MHC I complex reveals the mechanism of peptide editing in antigen presentation

We report the crystal structure of MHC I in complex with the peptide editor TAPBPR (TAP-binding protein–related), a tapasin homolog. TAPBPR remodels the peptide-binding groove of MHC I, resulting in the release of low-affinity peptide. Changes include groove relaxation, modifications of key binding pockets, and domain adjustments. This structure captures a peptide-receptive state of MHC I and provides insights into the mechanism of peptide editing by TAPBPR and, by analogy, tapasin.

Source: ScienceNOW - November 23, 2017 Category: Science Authors: Jiang, J., Natarajan, K., Boyd, L. F., Morozov, G. I., Mage, M. G., Margulies, D. H. Tags: Biochemistry, Immunology reports Source Type: news