title: [Crystallization and molecular structure of cyclic dodecadepsipeptide cyclo]D-Val-D-Hyi-Val-Hyi-(D-Val-Hyi-Val-D-Hyi)2-].2C3H60].
abstract: The crystal structure of a synthetic analogue of meso-valinomycin, crystallized with two acetone molecules, has been solved by X-ray direct methods. The trigonal crystals belong to the P32 space group, with the number of molecules in the unit cell z = 3, and cell dimensions a = b = 15,2085 A, c = 29,3250 A, alpha = beta = 90 degrees, gamma = 120 degrees. The standard (R) and weighted (Rw) factors after the structure refinement of atoms C, N, O in anisotropic thermal motion approximation and with the contribution from H atoms taken into account are 0,070 and 0,082, respectively. The molecule adopts an asymmetric conformations stabilized by six amide intramolecular hydrogen bonds NH ... OC of the 4----4 type; one of those is strong and the other are weakened in different extent. The side chains occupy the external pseudoaxial positions towards the cyclic frame of the molecule, whereas six free ester carbonyl groups have different orientations. In contrast to meso-valinomycin, the analogue under study has no specific binding site for metal ions. The isopropyl side chains of D-Hyi(2) and Hyi(4) residues effectively shield, from both sides, the access to the inner molecular cavity.
authors.forename: V Z
authors.initials: VZ
authors.lastname: Pletnev
authors.forename: I N
authors.initials: IN
authors.lastname: Tsygannik
authors.forename: I Iu
authors.initials: IIu
authors.lastname: Mikhaĭlova
authors.forename: V T
authors.initials: VT
authors.lastname: Ivanov
authors.forename: D A
authors.initials: DA
authors.lastname: Lengs
authors.forename: P
authors.initials: P
authors.lastname: Grokhul'skiĭ
authors.forename: V L
authors.initials: VL
authors.lastname: Diuéks
mesh_terms: D000595:Amino Acid Sequence; D003460:Crystallization; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D014634:Valinomycin / Q000031:analogs & derivatives; D014961:X-Ray Diffraction
chemical_list: D010456:Peptides, Cyclic; D014634:Valinomycin
vernacular_title: Kristallicheskaia i molekuliarnaia struktura tsiklicheskogo dodekadepsipeptida cyclo[D-Val-D-Hyi-(D-Val-Hyi-Val-D-Hyi)2-].2C3H6O.