title: Parity-violation energy of biomolecules-IV: protein secondary structure.
abstract: The parity-violation energy difference between enantiomeric forms of the same amino acid sequence, from the amyloid β-peptide involved in Alzheimer's disease, in both α-helix and β-sheet configurations, is investigated with ab-initio techniques. To this end, we develop an extension of the N2 computational scheme that selectively includes neighboring amino acids to preserve the relevant H-bonds. In agreement with previous speculations, it is found that the helical α structure is associated with larger parity-violation energy differences than the corresponding β form. Implications for the evolution of biological homochirality are discussed as well as the relative importance of various effects in determining the parity-violation energy.
authors.affiliation: Dipartamento di Chimica, Università di Modena e Reggio Emilia, Via G. Campi 183, Modena, Italy. cecco@unimo.it
authors.forename: Francesco
authors.initials: F
authors.lastname: Faglioni
authors.forename: Inmaculada García
authors.initials: IG
authors.lastname: Cuesta
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D016229:Amyloid beta-Peptides; D005075:Biological Evolution; D004583:Electrons; D006860:Hydrogen Bonding; D008956:Models, Chemical; D017433:Protein Structure, Secondary
chemical_list: D000596:Amino Acids; D016229:Amyloid beta-Peptides