title: A rationally designed oligopeptide shows significant conformational changes upon binding to sulphate ions.
abstract: Oligopeptides that interact with oxoanions were developed by rational design methods. The substrate-binding site of the enzyme purine nucleoside phosphorylase served as a model for the design of the ionophores. The amino acids involved in the complexation of oxoanions were linked through flexible spacer residues. These spacers were chosen such that the relative orientation of the interacting amino acids was conserved. Several peptide sequences were preselected based on intermolecular H-bond frequencies. These frequencies were calculated from molecular dynamics trajectories of the corresponding peptide-anion complexes and used to score the binding properties of the peptides. The most promising peptides were prepared using solid phase peptide synthesis. Anion binding of the peptide ionophores was screened using circular dichroism (CD) and confirmed by NMR spectroscopy. CD measurements performed in methanol revealed a significant conformational change of a linear undecapeptide upon binding to sulphate ions. Two-dimensional-NMR experiments confirmed that a conformation with high helical content is formed in the presence of sulphate ions. These conformational changes induced by the anion stimulate the development of new transduction mechanisms in chemical sensors.
authors.affiliation: Center for Chemical Sensors, Biosensors and bioAnalytical Chemistry, Swiss Federal Institute of Technology, Technoparkstr. 1, CH-8005 Zürich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Demuth
authors.forename: O
authors.initials: O
authors.lastname: Zerbe
authors.forename: D
authors.initials: D
authors.lastname: Rognan
authors.forename: R
authors.initials: R
authors.lastname: Söll
authors.forename: A
authors.initials: A
authors.lastname: Beck-Sickinger
authors.forename: G
authors.initials: G
authors.lastname: Folkers
authors.forename: U E
authors.initials: UE
authors.lastname: Spichiger
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D015374:Biosensing Techniques; D002942:Circular Dichroism; D015195:Drug Design; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D015398:Signal Transduction; D013431:Sulfates / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; D013431:Sulfates