Oxidatively-mediated in silico epimerization of a highly amyloidogenic segment in the human calcitonin hormone (hCT15-19)

Ahmad Kamal M Hamid; Joanna C Salvatore; Ke Wang; Prashantha Murahari; Andrea Guljas; Anita Rágyanszki; Michael Owen; Balázs Jójárt; Milán Szőri; Imre G Csizmadia; Béla Viskolcz; Béla Fiser

doi:10.1016/j.compbiolchem.2019.04.005

Oxidatively-mediated in silico epimerization of a highly amyloidogenic segment in the human calcitonin hormone (hCT_15-19)

Comput Biol Chem. 2019 Jun:80:259-269. doi: 10.1016/j.compbiolchem.2019.04.005. Epub 2019 Apr 8.

Authors

Affiliations

¹ Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
² School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London, E1 4NS, United Kingdom.
³ Department of Biochemistry, Faculty of Medicine, University of Toronto, 1 King's College Cir, Toronto, ON, M5S 1A8, Canada; Department of Molecular Medicine, Hospital for Sick Children, 1 King's College Cir, Toronto, ON, M5S 1A8, Canada.
⁴ Department of Chemistry, Faculty of Arts & Science, University of Toronto, 80 St George St, Toronto, ON, M5S 3H6, Canada; Department of Chemistry, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada. Electronic address: a.ragyanszki@utoronto.ca.
⁵ Department of Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany; CEITEC - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic.
⁶ Institute of Food Engineering, Faculty of Engineering, University of Szeged, H-6724 Szeged, Mars tér 7, Hungary.
⁷ Institue of Chemistry, Faculty of Materials Science and Engineering, University of Miskolc, H-3515 Miskolc, Hungary.
⁸ Department of Chemistry, Faculty of Arts & Science, University of Toronto, 80 St George St, Toronto, ON, M5S 3H6, Canada; Institue of Chemistry, Faculty of Materials Science and Engineering, University of Miskolc, H-3515 Miskolc, Hungary.
⁹ Institue of Chemistry, Faculty of Materials Science and Engineering, University of Miskolc, H-3515 Miskolc, Hungary; Ferenc Rákóczi II. Transcarpathian Hungarian Institute, Beregszász, Transcarpathia, 90200, Ukraine.

PMID: 31048244
DOI: 10.1016/j.compbiolchem.2019.04.005

Abstract

In order to study the effects of peptide exposure to oxidative attack, we chose a model reaction in which the hydroxyl radical discretely abstracts a hydrogen atom from the α-carbon of each residue of a highly amyloidogenic region in the human calcitonin hormone, hCT_15-19. Based on a combined Molecular Mechanics / Quantum Mechanics approach, the extended and folded L- and D-configuration and radical intermediate hCT_15-19 peptides were optimized to obtain their compactness, secondary structure and relative thermodynamic data. The results suggest that the epimerization of residues is generally an exergonic process that can explain the cumulative nature of molecular aging. Moreover, the configurational inversion induced conformational changes can cause protein dysfunction. The epimerization of the central residue to the D-configuration induced a hairpin structure in hCT_15-19, concomitant with a possible oligomerization of human calcitonin into Aβ(1-42)-like amyloid fibrils present in patients suffering from Alzheimer's disease.

Keywords: Aggregation; Amyloidosis; DFNKF; Molecular ageing; Oxidative-stress; Peptide.

MeSH terms

Amyloid beta-Peptides / chemistry
Amyloidogenic Proteins / chemistry*
Calcitonin / chemistry*
Density Functional Theory
Humans
Hydrogen Bonding
Models, Chemical
Molecular Dynamics Simulation
Oxidation-Reduction
Peptide Fragments / chemistry*
Protein Structure, Secondary
Stereoisomerism
Thermodynamics

Substances

Amyloid beta-Peptides
Amyloidogenic Proteins
Peptide Fragments
amyloid beta-protein (1-42)
calcitionin(15-19) peptide, human
Calcitonin