6ANN
Structure of cyclic D-Leu-N-methyl-D-Phe-2-Abz-D-Ala at 0.76 Angstrom
Summary for 6ANN
| Entry DOI | 10.2210/pdb6ann/pdb |
| Related | 6ANM |
| Descriptor | cyclic DLE-ZAE-BE2-DAL, ETHANOL (3 entities in total) |
| Functional Keywords | unnatural amino acid, peptidomimetic beta-turn, d-amino acid, tetrapeptide, cyclic peptide, de novo protein |
| Biological source | synthetic construct |
| Total number of polymer chains | 5 |
| Total formula weight | 2551.06 |
| Authors | Cameron, A.J.,Sarojini, V.,Squire, C.J. (deposition date: 2017-08-14, release date: 2017-11-15, Last modification date: 2023-11-15) |
| Primary citation | Cameron, A.J.,Squire, C.J.,Edwards, P.J.B.,Harjes, E.,Sarojini, V. Crystal and NMR Structures of a Peptidomimetic beta-Turn That Provides Facile Synthesis of 13-Membered Cyclic Tetrapeptides. Chem Asian J, 12:3195-3202, 2017 Cited by 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 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. PubMed: 29098772DOI: 10.1002/asia.201701422 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (0.76 Å) |
Structure validation
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