1PY4 image
Deposition Date 2003-07-08
Release Date 2004-05-04
Last Version Date 2024-11-20
Entry Detail
PDB ID:
1PY4
Title:
Beta2 microglobulin mutant H31Y displays hints for amyloid formations
Biological Source:
Source Organism:
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.90 Å
R-Value Free:
0.31
R-Value Work:
0.23
R-Value Observed:
0.24
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Beta-2-microglobulin precursor
Gene (Uniprot):B2M
Chain IDs:A, B, C, D
Chain Length:100
Number of Molecules:4
Biological Source:Homo sapiens
Primary Citation
beta2-microglobulin H31Y variant 3D structure highlights the protein natural propensity towards intermolecular aggregation
J.Mol.Biol. 335 1051 1064 (2004)
PMID: 14698299 DOI: 10.1016/j.jmb.2003.11.040

Abstact

beta2-Microglobulin (beta2m) is the non-covalently bound light chain of the human class I major histocompatibility complex (MHC-I). The natural turnover of MHC-I gives rise to the release of beta2m into plasmatic fluids and to its catabolism in the kidney. beta2m dissociation from the heavy chain of the complex is a severe complication in patients receiving prolonged hemodialysis. As a consequence of renal failure, the increasing beta2m concentrations can lead to deposition of the protein as amyloid fibrils. Here we characterize the His31-->Tyr human beta2m mutant, a non-natural form of beta2m that is more stable than the wild-type protein, displaying a ten-fold acceleration of the slow phase of folding. We report the 2.9A resolution crystal structure and the NMR characterization of the mutant beta2m, focussing on selected structural features and on the molecular packing observed in the crystals. Juxtaposition of the four mutant beta2m molecules contained in the crystal asymmetric unit, and specific hydrogen bonds, stabilize a compact protein assembly. Conformational heterogeneity of the four independent molecules, some of their mutual interactions and partial unpairing of the N-terminal beta-strand in one protomer are in keeping with the amyloidogenic properties displayed by the mutant beta2m.

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