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Biochemistry. 1999 May 4;38(18):5878-87.

A conformational change in the human major histocompatibility complex protein HLA-DR1 induced by peptide binding.

Author information

1
Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139, USA.

Abstract

To investigate a conformational change accompanying peptide binding to class II MHC proteins, we probed the structure of a soluble version of the human class II MHC protein HLA-DR1 in empty and peptide-loaded forms. Peptide binding induced a large decrease in the effective radius of the protein as determined by gel filtration, dynamic light scattering, and analytical ultracentrifugation. It caused a substantial increase in the cooperativity of thermal denaturation and induced alterations in MHC polypeptide backbone structure as determined by circular dichroism. These changes suggest a condensation of the protein around the bound peptide. An antibody specific for beta58-69 preferentially bound the empty protein, indicating that the peptide-induced conformational change involves the beta-subunit helical region. The conformational change may have important implications for the mechanisms of intracellular antigen presentation pathways.

PMID:
10231540
DOI:
10.1021/bi983048m
[Indexed for MEDLINE]

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