NMR structure of the channel-former zervamicin IIB in isotropic solvents

Spatial structure of the membrane channel-forming hexadecapeptide, zervamic in IIB, was studied by NMR spectroscopy in mixed solvents of different pola rity ranging from CDCl3/CD3OH (9:1, v/v) to CD3O/H2O (1:1, v/v), The result s show that in all solvents used the peptide has a very similar structure t hat is a bent amphiphilic helix with a mean backbone root mean square devia tion (rmsd) value of ca, 0.3 Angstrom. Side chains of Trp(1), Ile(2), Gln(3 ), Ile(5) and Thr(6) are mobile. The results are discussed in relation to t he validity of the obtained structure to serve as a building block of zerva micin IIB ion channels. (C) 2000 Federation of European Biochemical Societi es.