title: Asymmetric contribution of aromatic interactions stems from spatial positioning of the interacting aryl pairs in β-hairpins.
abstract: Isolated aromatic interactions in designed octapeptide β-hairpin scaffolds display a near-universal T-shaped face-to-edge geometry in all positional permutations, with the exception of aryl-Trp interactions. The heterogeneous asymmetric indole ring of Trp competes for a "shielding" face geometry, which lowers the scaffold stability in FtE aryl-Trp pairs. Assessment of the contributions of aryl pairs (in the absence of solvent-driven interactions) to the overall β-hairpin structure reveals the superiority of Trp-Phe and Trp-Tyr contributions over the well-established scaffold stabilization by Trp-Trp.
authors.affiliation: Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh 462023 (India).
authors.forename: Kamlesh Madhusudan
authors.initials: KM
authors.lastname: Makwana
authors.forename: Radhakrishnan
authors.initials: R
authors.lastname: Mahalakshmi
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D004151:Dipeptides / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary
chemical_list: D004151:Dipeptides; D009842:Oligopeptides; C029951:tryptophyltyrosine; C028281:phenylalanyltryptophan
keywords: NMR spectroscopy; aromatic interaction; circular dichroism; peptides; tryptophan