title: Influence of strand number on antiparallel beta-sheet stability in designed three- and four-stranded beta-sheets.
abstract: We describe experiments that probe whether antiparallel beta-sheet secondary structure becomes more stable as the number of strands increases. Several groups, including ours, have explored this issue with peptides designed to adopt three-stranded beta-sheet conformations, but the conclusions have not been consistent. In this study, we examine the effect on conformational stability of beta-sheet lengthening perpendicular to the strand direction via analysis of designed peptides that adopt three-stranded or four-stranded antiparallel beta-sheet conformations in aqueous solution. The findings reported here, along with the context provided by earlier studies, suggest that antiparallel beta-sheet does, in general, become more stable when the number of strands is increased from two to three. We show that this conclusion is not influenced by the rigidity of the loop segment used to link adjacent beta-strands (D-Pro-Gly versus Asn-Gly). We show that further extension, from three strands to four, leads to a further increase in antiparallel beta-sheet stability.
authors.affiliation: Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: Faisal A
authors.initials: FA
authors.lastname: Syud
authors.forename: Heather E
authors.initials: HE
authors.lastname: Stanger
authors.forename: Heather Schenck
authors.initials: HS
authors.lastname: Mortell
authors.forename: Juan F
authors.initials: JF
authors.lastname: Espinosa
authors.forename: John D
authors.initials: JD
authors.lastname: Fisk
authors.forename: Charles G
authors.initials: CG
authors.lastname: Fry
authors.forename: Samuel H
authors.initials: SH
authors.lastname: Gellman
mesh_terms: D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry*; D017433:Protein Structure, Secondary
chemical_list: D009842:Oligopeptides; D010446:Peptide Fragments