Human histocompatibility leukocyte antigen (HLA)-DM is a major histocompatibility complex (MHC)-like protein that catalyzes exchange of antigenic peptides from MHC class II molecules. To investigate the molecular details of this catalysis we created four covalent complexes between HLA-DM and the MHC class II allele DR1. We introduced a disulfide bond between the naturally occurring cysteine β46 on HLA-DM and an engineered cysteine on the end of a linker attached to either the NH2- or the COOH terminus of an antigenic peptide that is tightly bound on DR1. We find that when DM is attached to the NH2 terminus of the peptide, it can, for all linker lengths tested, catalyze exchange of the peptide with a half-life a few minutes (compared with uncatalyzed t1/2 > 100 h). This rate, which is several orders of magnitude greater than the one we obtain in solution assays using micromolar concentrations of HLA-DM, is dominated by a concentration independent factor, indicating an intramolecular catalytic interaction within the complex. A similar complex formed at the COOH terminus of the peptide shows no sign of DM-specific intramolecular catalysis. Restrictions on the possible interaction sites imposed by the length of the linkers indicate that the face of DR1 that accommodates the NH2 terminus of the antigenic peptide interacts with the lateral face of HLA-DM that contains cysteine β46.
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15 July 2002
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July 08 2002
Identification of the Lateral Interaction Surfaces of Human Histocompatibility Leukocyte Antigen (HLA)-DM with HLA-DR1 by Formation of Tethered Complexes That Present Enhanced HLA-DM Catalysis
Efstratios Stratikos,
Efstratios Stratikos
1Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
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Lidia Mosyak,
Lidia Mosyak
2Genetics Institute, Cambridge, MA 02140
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Dennis M. Zaller,
Dennis M. Zaller
3Department of Molecular Immunology, Merck Research Laboratories, Rahway, NJ 07065
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Don C. Wiley
Don C. Wiley
1Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
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Efstratios Stratikos
1Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
Lidia Mosyak
2Genetics Institute, Cambridge, MA 02140
Dennis M. Zaller
3Department of Molecular Immunology, Merck Research Laboratories, Rahway, NJ 07065
Don C. Wiley
1Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
Address correspondence to E. Stratikos, Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138. Phone: 617-495-1808; Fax: 617-495-9613; E-mail: [email protected]
*
Abbreviations used in this paper: DM, HLA-DM; DR1, HLA-DR1.
Received:
January 23 2002
Revision Received:
April 23 2002
Accepted:
May 30 2002
Online ISSN: 1540-9538
Print ISSN: 0022-1007
The Rockefeller University Press
2002
J Exp Med (2002) 196 (2): 173–183.
Article history
Received:
January 23 2002
Revision Received:
April 23 2002
Accepted:
May 30 2002
Citation
Efstratios Stratikos, Lidia Mosyak, Dennis M. Zaller, Don C. Wiley; Identification of the Lateral Interaction Surfaces of Human Histocompatibility Leukocyte Antigen (HLA)-DM with HLA-DR1 by Formation of Tethered Complexes That Present Enhanced HLA-DM Catalysis . J Exp Med 15 July 2002; 196 (2): 173–183. doi: https://doi.org/10.1084/jem.20020117
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