Thirteen synthetic pardaxin analogues were assayed for their ability to interact with model membranes of phosphatidylcholine. The results suggested the following: An amphipathic alpha-helix from isoleucine-14 to leucine-26 is responsible for most of the membrane perturbing properties of pardaxin. A hydrophobic N-terminal region enhances the activity of the isoleucine-14 to leucine-26 alpha-helix by binding the pardaxin molecule to the lipid bilayer. A bend centered around 12Ser-13Pro appears to create overall amphipathicity for the two different helical regions of pardaxin, but this contributes only slightly to potency. The C-terminal amino acids are unimportant for membrane perturbing activity and may be present only to enhance transportation in an aqueous environment prior to membrane binding in the native system.
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Journal
Biochimica et Biophysica Acta - Gene Regulatory Mechanisms