Role of the C-terminal 28 residues of beta2-microglobulin in amyloid fibril formation.
Beta2microglobulin (beta2m) is the major protein component of the fibrillar amyloid deposits isolated from patients diagnosed with dialysis-related amyloidosis (DRA). While investigating the molecular mechanism of amyloid fibril formation by beta2m, we found that the beta2m C-terminal peptide of 28 residues (cbeta2m) itself forms amyloid fibrils. When viewed by electron microscopy, cbeta2m aggregates appear as elongated unbranched fibers, the morphology typical for amyloids. Cbeta2m fibers stain with Congo red and show apple-green birefringence in polarized light, characteristic of amyloids. The observation that the beta2m C-terminal fragment readily forms amyloid fibrils implies that beta2m amyloid fibril formation proceeds via interactions of amyloid forming segments, which become exposed when the beta2m subunit is partially unfolded.
Ivanova
Magdalena I
MI
Howard Hughes Medical Institute and UCLA-DOE Institute of Genomics and Proteomics, 90095-1571, USA.
Gingery
Mari
M
Whitson
Lisa J
LJ
Eisenberg
David
D
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry* / Q000378:metabolism; D000682:Amyloid / Q000096:biosynthesis / Q000378:metabolism* / Q000648:ultrastructure; D001718:Birefringence; D002942:Circular Dichroism; D003224:Congo Red / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D008027:Light; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure; D012542:Scattering, Radiation; D013053:Spectrophotometry / Q000379:methods; D001613:beta 2-Microglobulin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure
D000596:Amino Acids; D000682:Amyloid; D011993:Recombinant Fusion Proteins; D001613:beta 2-Microglobulin; D003224:Congo Red