title: Solid-state conformations of aminosuccinyl peptides: crystal structure of tert-butyloxycarbonyl-L-leucyl-L-aminosuccinyl-L-phenylalaninami de.
abstract: The protected tripeptide tert-butyloxycarbonyl-L-leucyl-L-aminosuccinyl-L-phenylalaninamide crystallizes in the orthorhombic space group P2(1)2(1)2(1), with a = 6.214(3), b = 12.832(3), c = 33.094(4) A, Z = 4. The structure was solved by direct methods using MULTAN 80 and refined to an R value of 0.055 for 1458 reflections. The bond lengths and angles are in good agreement with the standard values. The peptide backbone adopts a type II' beta-bend conformation with a weak intramolecular hydrogen bond between the CO group of the leucyl residue and the C-terminal NH2 group. In agreement with previous studies, this structure confirms the high propensity of aminosuccinyl peptides to adopt a type II' beta-bend conformation. The role of this conformation in relation to the deamidation process in proteins is also discussed.
authors.forename: S
authors.initials: S
authors.lastname: Capasso
authors.forename: L
authors.initials: L
authors.lastname: Mazzarella
authors.forename: F
authors.initials: F
authors.lastname: Sica
authors.forename: A
authors.initials: A
authors.lastname: Zagari
mesh_terms: D008958:Models, Molecular; D009842:Oligopeptides; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D009842:Oligopeptides; C059751:tert-butyloxycarbonylleucyl-aminosuccinyl-phenylalaninamide