title: Aggregation of trypsin and trypsin inhibitor by Al cation.
abstract: Al cation may trigger protein structural changes such as aggregation and fibrillation, causing neurodegenerative diseases. We report the effect of Al cation on the solution structures of trypsin (try) and trypsin inhibitor (tryi), using thermodynamic analysis, UV-Visible, Fourier transform infrared (FTIR) spectroscopic methods and atomic force microscopy (AFM). Thermodynamic parameters showed Al-protein bindings occur via H-bonding and van der Waals contacts for trypsin and trypsin inhibitor. AFM showed that Al cations are able to force trypsin into larger or more robust aggregates than trypsin inhibitor, with trypsin 5±1 SE (n=52) proteins per aggregate and for trypsin inhibitor 8.3±0.7 SE (n=118). Thioflavin T test showed no major protein fibrillation in the presence of Al cation. Al complexation induced more alterations of trypsin inhibitor conformation than trypsin.
authors.affiliation: Department of Chemistry-Biochemistry, Physics University of Québec, Trois-Rivières, C. P. 500, TR, Quebec G9A 5H7, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Chanphai
authors.affiliation: Department of Physics and Atmospheric Science, Sir James Dunn Building Dalhousie University, Lord Dalhousie Drive, Halifax NS B3H 4R2, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Kreplak
authors.affiliation: Department of Chemistry-Biochemistry, Physics University of Québec, Trois-Rivières, C. P. 500, TR, Quebec G9A 5H7, Canada. Electronic address: tajmirri@uqtr.ca.
authors.forename: H A
authors.initials: HA
authors.lastname: Tajmir-Riahi
mesh_terms: D000535:Aluminum / Q000494:pharmacology*; D002412:Cations; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D066263:Protein Aggregation, Pathological / Q000209:etiology*; D011485:Protein Binding / Q000187:drug effects; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014357:Trypsin / Q000737:chemistry*; D014361:Trypsin Inhibitors / Q000737:chemistry*
chemical_list: D002412:Cations; D012996:Solutions; D014361:Trypsin Inhibitors; D000535:Aluminum; D014357:Trypsin
keywords: AFM; Aggregation; Al cation; Spectroscopy; Thermodynamic; Trypsin; Trypsin inhibitor