X-ray crystallographic characterization of rhesus macaque MHC Mamu-A*02 complexed with an immunodominant SIV-Gag nonapeptide.

Simian immunodeficiency virus (SIV) in the rhesus macaque is regarded as a classic animal model, playing a crucial role in HIV vaccine strategies and therapeutics by characterizing various cytotoxic T-lymphocyte (CTL) responses in macaque monkeys. However, the availability of well documented structural reports focusing on rhesus macaque major histocompatibility complex class I (MHC I) molecules remains extremely limited. Here, a complex of the rhesus macaque MHC I molecule (Mamu-A*02) with human beta2m and an immunodominant SIV-Gag nonapeptide, GESNLKSLY (GY9), has been crystallized. The crystal diffracts X-rays to 2.7 A resolution and belongs to space group C2, with unit-cell parameters a = 124.11, b = 110.45, c = 100.06 A, and contains two molecules in the asymmetric unit. The availability of the structure, which is being solved by molecular replacement, will provide new insights into rhesus macaque MHC I (Mamu-A*02) presenting pathogenic SIV peptides.