title: Design strategies for the sequence-based mimicry of side-chain display in protein β-sheets by α/β-peptides.
abstract: The sophistication of folding patterns and functions displayed by unnatural-backbone oligomers has increased tremendously in recent years. Design strategies for the mimicry of tertiary structures seem within reach; however, a general method for the mimicry of sheet segments in the context of a folded protein is an unmet need preventing realization of this goal. Previous work has shown that 1→1 α→β-residue substitutions at cross-strand positions in a hairpin-forming α-peptide sequence can generate an α/β-peptide analogue that folds in aqueous conditions but with a change in side-chain display relative to the natural sequence; this change would prevent application of single β-residue substitutions in a larger protein. Here, we evaluate four different substitution strategies based on replacement of αα dipeptide segments for the ability to retain both sheet folding encoded by a parent α-peptide sequence as well as nativelike side-chain display in the vicinity of the β-residue insertion point. High-resolution structure determination and thermodynamic analysis of folding by multidimensional NMR suggest that three of the four designs examined are applicable to larger proteins.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States.
authors.forename: George A
authors.initials: GA
authors.lastname: Lengyel
authors.forename: W Seth
authors.initials: WS
authors.lastname: Horne
mesh_terms: D000595:Amino Acid Sequence; D008958:Models, Molecular; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D010455:Peptides; D011506:Proteins