Elucidation of the Solution Conformations of Loloatin C by NMR Spectroscopy and Molecular Simulation

Autor: Heru Chen, Richard K. Haynes, Guang Zhu, Jürgen Scherkenbeck, Kong H. Sze
Rok vydání: 2004
Předmět:
Zdroj: European Journal of Organic Chemistry. 2004:31-37
ISSN: 1099-0690
1434-193X
DOI: 10.1002/ejoc.200300476
Popis: NMR experiments combined with molecular simulation with X-PLOR have been employed to determine the solution conformation of the cyclic decapeptide loloatin C in three different solutions. In DMSO, the molecule possesses a hydrophobic aromatic “wall” consisting of Trp6 and Phe7, and a type I β-turn structure involving Val1, Trp10, Asp9 and Asn8 with a hydrophobic head at Val1/Trp10 and a hydrophilic tail at Asp9 and Asn8; another type II′ β-turn was also located between Leu3, Tyr4, Pro5, and Trp6. In 70/30 [D3]TFE/H2O, however, loloatin C possesses a dumbbell structure with all the hydrophobic side chains projecting upward on one side, forming a hydrophobic surface, and the hydrophilic side chains projecting to the other side, together with most of carbonyl oxygen atoms, thereby forming a hydrophilic surface. However, in 30:70 [D3]TFE/H2O, loloatin C possesses an inverse γ-turn incorporating Tyr4, Pro5, and Trp6, a hydrophobic zone involving the side chains of Leu3, Trp6, Trp10, and Phe7 and a hydrophilic tail involving the hydrophilic side chains of Orn2, Asn8, and Asp9. The amphiphilicity of the dumbbell structure in 70/30 [D3]TFE/H2O is of interest in relation to the antibiotic activity of loloatin C. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Databáze: OpenAIRE
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