title: On the helix-coil transition in alanine based polypeptides in gas phase.
abstract: Using multicanonical simulations, the authors study the effect of charged end groups on helix formation in alanine based polypeptides. They confirm earlier reports that neutral polyalanine exhibits a pronounced helix-coil transition in gas phase simulations. Introducing a charged Lys+ at the C terminal stabilizes the alpha helix and leads to a higher transition temperature. On the other hand, adding the Lys+ at the N terminal inhibits helix formation. Instead, a more globular structure was found. These results are in agreement with recent experiments on alanine based polypeptides in gas phase. They indicate that present force fields describe accurately the intramolecular interactions in proteins.
authors.affiliation: Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA. yawei@mtu.edu
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Wei
authors.forename: Walter
authors.initials: W
authors.lastname: Nadler
authors.forename: Ulrich H E
authors.initials: UH
authors.lastname: Hansmann
mesh_terms: D000409:Alanine / Q000737:chemistry*; D005740:Gases; D006860:Hydrogen Bonding; D008239:Lysine / Q000737:chemistry*; D015233:Models, Statistical; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D005740:Gases; D010455:Peptides; D008239:Lysine; D000409:Alanine