Molecular Dynamics and Structure of Peptide Hormones at Membrane-Water Interfaces
Peptide hormones of low molecular weight are among the most flexible polypeptides in living organisms (Blundell and Wood, 1982). In order to express their specific functions they must acquire a more restricted bioactive conformation conformation (Kaiser and Kezdy, 1983; 1984). As recently pointed out by Braun et al. (1983), it appears rather unlikely that the initial interaction of peptide hormones with the target cells will result in the immediate formation of a specific complex with the membrane-bound receptors at the plasma membrane level. Thermodynamic as well as kinetic considerations indeed suggest that the lipid matrix of the cell plasma membrane may have functional implications in the transmembrane signaling process by playing as an “antenna” for the capture of the peptide (Sargent and Schwyzer, 1986). Moreover, the interaction of the peptide with the membrane lipids may select a bioactive conformational state among the many existing in aqueous solutions (Behnam and Deber, 1984; Deber and Behnam, 1985; Schwyzer, 1986). The interfacial characteristics of the lipid matrix (charge density, head-group packing, availability of hydrogen-bond forming groups, mobility of the interfacial water molecules and local proton activity) are likely to be involved in the selection of a dynamic and conformational state of the peptide.
KeywordsReverse Micelle Peptide Hormone Fluorescence Anisotropy Cell Plasma Membrane Lipid Matrix
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- Kaiser, E. T. and Kezdy, J. F., 1983, Proc. Natl. Acad. Sci. U.S.A., 83:5774.Google Scholar