Download MendeleyCrystal and NMR Structures of a Peptidomimetic beta-Turn That Provides Facile Synthesis of 13-Membered Cyclic Tetrapeptides.
Cameron, A.J., Squire, C.J., Edwards, P.J.B., Harjes, E., Sarojini, V.(2017) Chem Asian J 12: 3195-3202
- PubMed: 29098772
- DOI: https://doi.org/10.1002/asia.201701422
- Primary Citation of Related Structures:
6ANM, 6ANN - PubMed Abstract:
Herein we report the unique conformations adopted by linear and cyclic tetrapeptides (CTPs) containing 2-aminobenzoic acid (2-Abz) in solution and as single crystals. The crystal structure of the linear tetrapeptide H 2 N-d-Leu-d-Phe-2-Abz-d-Ala-COOH (1) reveals a novel planar peptidomimetic β-turn stabilized by three hydrogen bonds and is in agreement with its NMR structure in solution. While CTPs are often synthetically inaccessible or cyclize in poor yield, both 1 and its N-Me-d-Phe analogue (2) adopt pseudo-cyclic frameworks enabling near quantitative conversion to the corresponding CTPs 3 and 4. The crystal structure of the N-methylated peptide (4) is the first reported for a CTP containing 2-Abz and reveals a distinctly planar 13-membered ring, which is also evident in solution. The N-methylation of d-Phe results in a peptide bond inversion compared to the conformation of 3 in solution.
Organizational Affiliation:
School of Chemical Sciences, The University of Auckland, Auckland, 1142, New Zealand.
