An amyloid-forming segment of beta2-microglobulin suggests a molecular model for the fibril.
In humans suffering from dialysis-related amyloidosis, the protein beta2-microglobulin (beta2M) is deposited as an amyloid; however, an amyloid of beta2M is unknown in mice. beta2M sequences from human and mouse are 70% identical, but there is a seven-residue peptide in which six residues differ. This peptide from human beta2M forms amyloid in vitro, whereas the mouse peptide does not. Substitution of the human peptide for its counterpart in the mouse sequence results in the formation of amyloid in vitro. These results show that a seven-residue segment of human beta2M is sufficient to convert beta2M to the amyloid state, and that specific residue interactions are crucial to the conversion. These observations are consistent with a proposed Zipper-spine model for beta2M amyloid, in which the spine of the fibril consists of an anhydrous beta-sheet.
Ivanova
Magdalena I
MI
Howard Hughes Medical Institute and University of California-Department of Energy Institute of Genomics and Proteomics, Box 951570, University of California, Los Angeles, CA 90095, USA.
Sawaya
Michael R
MR
Gingery
Mari
M
Attinger
Antoine
A
Eisenberg
David
D
D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014961:X-Ray Diffraction; D001613:beta 2-Microglobulin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D000682:Amyloid; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D001613:beta 2-Microglobulin