title: Crystal structures of peptidic catalysts of the H-dPro-Pro-Xaa type.
abstract: Crystal structures of catalytically active tripeptides of the general type H-dPro-Pro-Xaa and related N-acetylated analogs were compared. The influence of acylation at the N-terminus, the nature of the C-terminal residue, coordinating groups, and intramolecular hydrogen bonds on the conformation of the tripeptides was examined. Regardless of the presence or absence of stabilizing intramolecular H-bonds or n → π* interactions, all of the analyzed peptides share a β-turn-like conformation, which highlights the structural rigidity of the dPro-Pro motif and its value for conformational preorganization. The C-terminal residues and coordinating moieties were found to affect the turn-conformation, which suggests that H-dPro-Pro-Xaa type peptides are sufficiently flexible to adopt distinctly different but related conformations.
authors.affiliation: Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, CH-8093, Zürich, Switzerland.
authors.forename: Claudio E
authors.initials: CE
authors.lastname: Grünenfelder
authors.affiliation: Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, CH-8093, Zürich, Switzerland.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Kisunzu
authors.affiliation: Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, CH-8093, Zürich, Switzerland.
authors.forename: Nils
authors.initials: N
authors.lastname: Trapp
authors.affiliation: Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, CH-8093, Zürich, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Kastl
authors.affiliation: Laboratory of Organic Chemistry, D-CHAB, ETH Zürich, Vladimir-Prelog-Weg 3, CH-8093, Zürich, Switzerland.
authors.forename: Helma
authors.initials: H
authors.lastname: Wennemers
mesh_terms: D000595:Amino Acid Sequence; D002384:Catalysis; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D010455:Peptides
keywords: catalysis; crystal structures; peptides; proline; β-turn conformation