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Publication Abstract from PubMed

The rat MHC class Ia molecule RT1-Aa has the unusual capacity to bind long peptides ending in arginine, such as MTF-E, a thirteen-residue, maternally transmitted minor histocompatibility antigen. The antigenic structure of MTF-E was unpredictable due to its extraordinary length and two arginines that could serve as potential anchor residues. The crystal structure of RT1-Aa-MTF-E at 2.55 A shows that both peptide termini are anchored, as in other class I molecules, but the central residues in two independent pMHC complexes adopt completely different bulged conformations based on local environment. The MTF-E epitope is fully exposed within the putative T cell receptor (TCR) footprint. The flexibility demonstrated by the MTF-E structures illustrates how different TCRs may be raised against chemically identical, but structurally dissimilar, pMHC complexes.

Two different, highly exposed, bulged structures for an unusually long peptide bound to rat MHC class I RT1-Aa.,Speir JA, Stevens J, Joly E, Butcher GW, Wilson IA Immunity. 2001 Jan;14(1):81-92. PMID:11163232^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.