The isolated major histocompatibility complex class I alpha 3 domain bindsbeta 2m and CD8 alpha alpha dimers

The MHC class I molecule plays a crucial role in cytotoxic lymphocyte funct ion. The heavy chain of the MHC class I molecule can form many non-covalent interactions with other molecules on multiple domains and surfaces. We hav e generated an isolated alpha 3 domain of a murine MHC class I molecule and evaluated the contribution of this domain to binding with the MHC class I light chain, beta 2m, and CD8. The alpha 3 domain binds beta 2m at a thousa nd-fold higher concentration than the whole MHC, and binds CD8 alpha alpha with a dependence on the alpha 3 CD loop. Our results are relevant for mode ls of MHC folding and CD8-MHC function. The study of individual domains of complex molecules is an important strategy for understanding their dynamic structure and function. Published by Elsevier Science Ltd.