Crystal and molecular structure of tert.-butyloxycarbonyl-L-hydroxy-prolyl-alpha-aminoisobutyryl-alpha-aminoisobutyryl-L-phenylalaninol.
The crystal structure of the synthetic tetrapeptide, Boc-Hyp-Aib-Aib-Phol, an analogue of the C-terminal tetrapeptide in the antibiotic antiamoebin I, was determined as part of a study of the conformation of peptaibophol antibiotics. The crystals are orthorhombic, space group P212121, with cell parameters a = 16.576 (1) A, b = 17.657 (1) A, c = 10.435 (1) A, V = 3053.9 (2) A3, Z = 4, Dc = 1.163 g.cm-3. The three amino acids from a single turn of a 3 10-helix, stabilized by two intramolecular hydrogen bonds. The Aib residues adopt the usual conformation in the region between the 3 10- and alpha-helices. The terminal hydroxy methyl group of the phenylalaninol residue is disordered. The position of the benzyl side chain of the amino alcohol relative to the backbone corresponds to a conformation also observed in phenylalanine residues.
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents; D008958:Models, Molecular; D009842:Oligopeptides / Q000138:chemical synthesis*; D054848:Peptaibols; D010455:Peptides; D010456:Peptides, Cyclic; D011487:Protein Conformation; D014961:X-Ray Diffraction
D000900:Anti-Bacterial Agents; D009842:Oligopeptides; D054848:Peptaibols; D010455:Peptides; D010456:Peptides, Cyclic; C006596:antiamoebin; C035641:tert-butyloxycarbonyl-hydroxyprolyl-alpha-aminoisobutyryl-alpha-aminoisobutyryl-phenylalaninol