In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 96, No. 13 ( 1999-06-22), p. 7445-7450
Abstract:
Class II MHC molecules are known to exist in conformational variants. “Floppy” and “compact” forms of murine MHC molecules, for example, are discriminated by their migration behavior on SDS/PAGE and represent empty and ligand-loaded forms. Here we show that formation of distinctly faster-migrating ligand complexes (F-forms) rather than the normal compact (C-) forms of HLA-DR1 or -DR4 results from extensions of minimal peptide epitopes (such as HA306-318 or IC106-120) by ≈10 amino acids at either the N or the C terminus. Two similar but distinct F-forms (F I and F II ) were detected, depending on the site of the extension. Both F-forms were characterized by increased surface hydrophobicity and reduced SDS-stability. Native gel separations and size exclusion chromatography indicated that the F-forms had increased hydrodynamic radii compared with the C-form and an apparent size similar to that of empty MHC molecules. The regions on the ligand overhangs responsible for the effect began at a distance of ≈5 amino acids on either side of the epitopes, comprised 4–8 amino acids (i.e., a total overhang of 9–14), and did not have a particular sequence preference. The possible functional significance of these forms is discussed.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.96.13.7445
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
1999
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
