X-RAY-DIFFRACTION STUDIES OF FIBRILS FORMED FROM PEPTIDE-FRAGMENTS OF TRANSTHYRETIN

Two synthetic peptide fragments of the plasma protein transthyretin (TTR), previously shown to form fibrillar structures in vitro, have been examined using electron microscopy and X-ray diffraction. The fibrils displayed all characteristics of cross β-sheet conformation with antiparallel strand spacing of 4.7 Å and intersheet spacings of 8 - 10 Å as well as reflections indicating further lateral repeating units. A third peptide containing a substitution equivalent to a mutation in TTR known to increase the propensity of TTR to form amyloid was also examined. It also formed fibrils and showed similar cross β-sheet structure, but with closer intersheet packing than its native equivalent. © 1993 Academic Press. All rights reserved.