title: Why Is the C-terminus of Abeta(1-42) more unfolded than that of Abeta(1-40)? Clues from hydrophobic interaction.
abstract: Abeta(1-40) and Abeta(1-42) are the main forms of amyloid beta (Abeta) peptides in the brain of Alzheimer's patients; however, the latter possesses much stronger aggregation and deposition propensity than the former, which is partially attributed to the more unfolded C-terminus of Abeta(1-42) than that of Abeta(1-40). To explore the physical basis underlying the different dynamic behaviors of both Abeta peptides, parallel molecular dynamics (MD) simulations on Abeta(1-40) and Abeta(1-42) were performed to investigate their thermal unfolding processes. It is revealed that the addition of residues 41 and 42 in Abeta(1-42) disrupts the C-terminal hydrophobic core, which triggers the unraveling of the C-terminal helix of Abeta(1-42). This conclusion is supported by the MD simulation on the I41A mutant of Abeta(1-42), in which the C-terminal helix possesses relatively higher conformational stability than that of wild type Abeta(1-42) owing to the change in hydrophobic interaction patterns.
authors.affiliation: Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Center for Advanced Study, Shandong University of Technology, Zibo, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
authors.forename: Hong-Fang
authors.initials: HF
authors.lastname: Ji
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Zhang
mesh_terms: D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017510:Protein Folding; D017434:Protein Structure, Tertiary
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42)