Conformation for a β-cyclodextrin monosubstituted with a cyclic dipeptide(649 views) Di Blasio B, Pavone V, Nastri F, Isernia C, Saviano M, Pedone C, Cucinotta V, Impellizzeri G, Rizzarelli E, Vecchio G
P Natl Acad Sci Usa (ISSN: 0027-8424, 1091-6490, 0027-8424print), 1992 Sep 1; 89(15): 7218-7221.
Affiliations: Dipartimento di Chimica, Università di Napoli, via Mezzocannone, 4, 80134 Napoli, Italy
Dipartimento Scienze Chimiche, Università di Catania, Catania, Italy
Ist. Stud. Sostanze N., Consiglio Nazionale Della Ricerche, Catania, Italy
References: Not available.
Conformation for a β-cyclodextrin monosubstituted with a cyclic dipeptide
The structural characterization of a β-cyclodextrin monosubstituted with the peptide cyclo(L-His-L-Leu) is reported. This work provides an x-ray example of a covalently bound group that folds in such a way that the terminal apolar side chain is retained in the hydrophobic interior of the cone-shaped cyclodextrin cavity. 6-Deoxy-6-cyclo(L-histidyl-L-leucyl)-β-cyclodextrin crystallizes in the space group P1 with cell dimensions a = 14.728(8) Å, b = 15.084(7) Å, c = 18.182(10) Å, α = 94.36(6)°, β= 95.81(5)°, γ = 116.08(9)°; overall isotropic agreement R = 10.6% for 5703 observed reflections (Fo > 3σ). The molecular structure consists of two independent molecules with the formula C54H86N4O36·7.25H 2O. Each molecule assumes a "sleeping swan"-like overall shape with the hydrophobic leucine side chain inserted inside the cavity of the macrocycle. The two independent units give rise to a head-to-tail dimer linked by hydrogen bonds occurring between primary and secondary hydroxyl groups of the two monomers. The packing of the dimers produces cavities containing water molecules. There are infinite hydrophilic channels running in the crystal, which is similar to what is found in the structures of cyclic peptides.
Conformation for a β-cyclodextrin monosubstituted with a cyclic dipeptide
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Conformation for a β-cyclodextrin monosubstituted with a cyclic dipeptide