[en] In order to better understand the driving forces that determine the alignment of amphipathic helical polypeptides with respect to the surface of phospholipid bilayers, lysine-containing peptide sequences were designed, prepared by
solid-phase chemical synthesis, and reconstituted into membranes. CD spectroscopy
indicates that all peptides exhibit a high degree of helicity in the presence of SDS micelles or POPC small unilamellar vesicles. Proton-decoupled (31)P-NMR solid-state NMR spectroscopy demonstrates that in the presence of peptides liquid
crystalline phosphatidylcholine membranes orient well along glass surfaces. Thenorientational distribution and dynamics of peptides labeled with (15)N at selected sites were investigated by proton-decoupled (15)N solid-state NMR spectroscopy. Polypeptides with a single lysine residue adopt a transmembrane orientation, thereby locating this polar amino acid within the core region of the bilayer. In contrast, peptides with > or = 3 lysines reside along the surface of the membrane. With 2 lysines in the center of an otherwise hydrophobic amino acid
sequence the peptides assume a broad orientational distribution. The energy of lysine discharge, hydrophobic, polar, and all other interactions are estimated to quantitatively describe the polypeptide topologies observed. Furthermore, a molecular modeling algorithm based on the hydrophobicities of atoms in a continuous hydrophilic-hydrophobic-hydrophilic potential describes the experimentally observed peptide topologies well.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Vogt, B.
Ducarme, P.
Schinzel, S.
Brasseur, Robert ; Université de Liège - ULiège > Gembloux Agro-Bio Tech
Bechinger, B.
Language :
English
Title :
The Topology Of Lysine-Containing Amphipathic Peptides In Bilayers By Circular Dichroism, Solid-State Nmr, And Molecular Modeling
Bechinger, B. 1996. Towards membrane protein design: pH dependent topology of histidine-containing polypeptides. J. Mol. Biol. 263: 768-775.
Bechinger, B. 1997. Structure and functions of channel-forming polypeptides: magainins, cecropins, melittin and alamethicin. J. Membr. Biol. 156:197-211.
Bechinger, B. 1999. The structure, dynamics and orientation of antimicrobial peptides in membranes by solid-state NMR spectroscopy. Biochim. Biophys. Acta. 1462:157-183.
Bechinger, B. 2000. Biophysical investigations of membrane perturbations by polypeptides using solid-state NMR spectroscopy. Mol. Membr. Biol. in press.
Zhang, Y. P., R. N. Lewis, G. D. Henry, B. D. Sykes, R. S. Hodges, and R. N. McElhaney. 1995. Peptide models of helical hydrophobic transmembrane segments of membrane proteins. 1. Studies of the conformation, intrabilayer orientation, and amide hydrogen exchangeability of Ac-K2-(LA)12-K2-amide. Biochemistry. 34:2348-2361.