title: Identification of an amyloid fibril forming segment of human Pmel17 repeat domain (RPT domain).
abstract: Pmel17 is the major component of functional amyloid fibrils that have an important role during pigment deposition. Pmel17 polymerization is promoted within the mildly acidic conditions of melanosomes, organelles located in pigment-specific cells. A repeat domain (RPT domain) of Pmel17, rich in glutamic acid residues has been extensively associated with the formation of the fibrous matrix. Here, we examine the RPT domain of human Pmel17 in order to provide information on this mechanism. Specifically, we have identified an aggregation-prone peptide segment ((405) VSIVVLSGT(413) ), close to the C-terminal part of the RPT domain. Experimental results utilizing electron microscopy, X-ray fiber diffraction, Congo red staining and ATR FT-IR spectroscopy indicate that this peptide segment self-assembles forming fibrils with evident amyloidogenic properties. Conclusively, our results demonstrate that the (405) VSIVVLSGT(413) peptide segment possibly has an essential role in RPT domain fibrillogenesis.
authors.affiliation: Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens, 157 01, Greece.
authors.forename: Nikolaos N
authors.initials: NN
authors.lastname: Louros
authors.affiliation: Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens, 157 01, Greece.
authors.forename: Vassiliki A
authors.initials: VA
authors.lastname: Iconomidou
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction; D058951:gp100 Melanoma Antigen / Q000737:chemistry*
chemical_list: D000682:Amyloid; C548637:PMEL protein, human; D058951:gp100 Melanoma Antigen
keywords: amyloid fibrils; electron microscopy; melanin; melanosomes; “aggregation-prone” peptide-analogue