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Accueil > Publications > Recherche par années > Années 1990 > 1994

Bonmatin, JM ; Genest, M ; Labbe, H ; Ptak, M

Solution 3-dimensional structure of surfactin - a cyclic lipopeptide studied by h-1-NMR, distance geometry, and molecular-dynamics

Biopolymers 34 (7) 975-986

par Administrateur - publié le

Abstract :

The solution three-dimensional structure of the protonated [Leu7]-surfactin, an heptapeptide extracted from Bacillus subtilis, has been determined from two-dimensional H-1-nmr performed in H-2(6)-dimethylsulfoxide and combined with molecular modeling. Experimental data included 9 coupling constants, 61 nuclear Overhauser effect derived distances, NH temperature coefficients, and C-13 relaxation times. Two distance geometry (DISMAN) protocols converged toward models of the structure and the best of them were refined by restrained and unrestrained molecular dynamics (GROMOS). Two structures in accord with the set of experimental constraints are presented. Both are characterized by a ’’horse saddle’’ topology for ring atoms on which are attached the two polar Glu and Asp side chains showing an orientation clearly opposite to that of the C-11-13 aliphatic chain. Amphipathic and surface properties of surfactin are certainly related to the existence of such minor polar and a major hydrophobic domains. The particular ’’claw’’ configuration of acidic residues observed in surfactin gives important clues for the understanding of its cation binding and transporting ability. (C) 1994 John Wiley and Sons, Inc.