title: BetaCore, a designed water soluble four-stranded antiparallel beta-sheet protein.
abstract: BetaCore is a designed approximately 50-residue protein in which two BPTI-derived core modules, CM I and CM II, are connected by a 22-atom cross-link. At low temperature and pH 3, homo- and heteronuclear NMR data report a dominant folded ('f') conformation with well-dispersed chemical shifts, i, i+1 periodicity, numerous long-range NOEs, and slowed amide hydrogen isotope exchange patterns that is a four-stranded antiparallel beta-sheet with nonsymmetrical and specific association of CM I and CM II. BetaCore 'f' conformations undergo reversible, global, moderately cooperative, non-two-state thermal transitions to an equilibrium ensemble of unfolded 'u' conformations. There is a significant energy barrier between 'f' and 'u' conformations. This is the first designed four-stranded antiparallel beta-sheet that folds in water.
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Natàlia
authors.initials: N
authors.lastname: Carulla
authors.forename: Clare
authors.initials: C
authors.lastname: Woodward
authors.forename: George
authors.initials: G
authors.lastname: Barany
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007611:Aprotinin / Q000737:chemistry; D002417:Cattle; D019281:Dimerization; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010091:Oximes; D015202:Protein Engineering; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*; D012995:Solubility; D013696:Temperature
chemical_list: D010091:Oximes; D011506:Proteins; D007611:Aprotinin