title: Crystal and molecular structure of tert.-butyloxycarbonyl-L-prolyl-alpha-aminoisobutyryl-L-alanyl-alpha- aminoisobutyrate methyl ester.
abstract: Boc-Pro-Aib-Ala-Aib-OMe crystallizes in the orthorhombic space group P2(1)2(1)2 with cell dimensions a = 17.701 (3) A, b = 17.476 (4) A, c = 9.686 (2) A, V = 2996.3 A3. The first three residues form a single turn of a 3(10)-helix stabilized by two intramolecular hydrogen bonds. Comparison of the conformation of the methyl ester of the tetrapeptide with that of its benzyl ester shows differences in the individual torsion angles of up to 29 degrees, although the overall conformation is conserved.
mesh_terms: D000408:Alamethicin; D003460:Crystallization; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009842:Oligopeptides; D010446:Peptide Fragments; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D009842:Oligopeptides; D010446:Peptide Fragments; D000408:Alamethicin; C039937:tert-butyloxycarbonyl-prolyl-2-aminoisobutyryl-alanyl-2-aminoisobutyrate methyl ester