title: Hydrogen Bonding Cooperativity in polyQ β-Sheets from First Principle Calculations.
abstract: Polyglutamine β-sheet aggregates are associated with the derangement of Huntington's disease. The effect of cooperativity of the H-bond network formed by both backbone and side chain groups is expected to be important for the structure and energetics of the aggregates. So far, no direct description and/or quantification of the effect is yet available. By performing DFT and hybrid DFT/MM simulations of polyglutamine β-sheet structures in vacuo and in aqueous solution, we observe that the cooperativity of glutamine side chains affects both the directions perpendicular and parallel to the backbone. This behavior is not usually observed in β sheets and may provide significant extra-stabilization together with explaining some of the unique properties of polyglutamine aggregation.
authors.affiliation: Statistical and Biological Physics Sector, International School for Advanced Studies (SISSA-ISAS) and CNR-IOM-DEMOCRITOS National Simulation Center, Trieste, Italy, Via Beirut 2-4, Trieste, Italy, German Research School for Simulation Science, FZ-Juelich and RWTH, Germany, Italian Institute of Technology-SISSA Unit, Via Beirut 2-4, Trieste, Italy, and National Institute for Medical Research, The Ridgeway London, NW71AA, United Kingdom.
authors.forename: Giulia
authors.initials: G
authors.lastname: Rossetti
authors.affiliation: Statistical and Biological Physics Sector, International School for Advanced Studies (SISSA-ISAS) and CNR-IOM-DEMOCRITOS National Simulation Center, Trieste, Italy, Via Beirut 2-4, Trieste, Italy, German Research School for Simulation Science, FZ-Juelich and RWTH, Germany, Italian Institute of Technology-SISSA Unit, Via Beirut 2-4, Trieste, Italy, and National Institute for Medical Research, The Ridgeway London, NW71AA, United Kingdom.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Magistrato
authors.affiliation: Statistical and Biological Physics Sector, International School for Advanced Studies (SISSA-ISAS) and CNR-IOM-DEMOCRITOS National Simulation Center, Trieste, Italy, Via Beirut 2-4, Trieste, Italy, German Research School for Simulation Science, FZ-Juelich and RWTH, Germany, Italian Institute of Technology-SISSA Unit, Via Beirut 2-4, Trieste, Italy, and National Institute for Medical Research, The Ridgeway London, NW71AA, United Kingdom.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Pastore
authors.affiliation: Statistical and Biological Physics Sector, International School for Advanced Studies (SISSA-ISAS) and CNR-IOM-DEMOCRITOS National Simulation Center, Trieste, Italy, Via Beirut 2-4, Trieste, Italy, German Research School for Simulation Science, FZ-Juelich and RWTH, Germany, Italian Institute of Technology-SISSA Unit, Via Beirut 2-4, Trieste, Italy, and National Institute for Medical Research, The Ridgeway London, NW71AA, United Kingdom.
authors.forename: Paolo
authors.initials: P
authors.lastname: Carloni