Amino acid sequences which promote and prevent the binding and membrane insertion of surface-active peptides: Comparison of melittin and promelittin

Caroline Wolfe, Josep Cladera, Paul O'Shea*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)

Abstract

The temporal sequence of molecular events involved in the interactions of a number of related peptides with membranes are revealed using two complementary fluorescence techniques. Comparative studies are reported of the interactions of melittin, promelittin and a melittin analogue with trp-19 replaced with lie and the n-terminal gly replaced with a trp residue, with phosphatidylcholine membranes. It is shown that the interaction of the n-terminal region of melittin rapidly binds and inserts into the body of the membrane with a rate constant of around 367 s-1. This is followed by a slightly slower membrane insertion of the trp-19 region with a rate constant of around 112 s-1. The positive charges of the melittin molecule then come into close proximity with the membrane with rate constants around 27 s-1. Finally, these charged regions insert into the hydrophobic core of the membrane with rate constants of about 0.3 s-1. The effect of incorporating net negative charge onto the membrane surface in the form of 15 mole % phosphatidylserine, augments by about threefold, the binding of the charged domains of the melittin molecule. The observations of the melittin interactions are compared with the melittin precursor protein, promelittin. Sections of the promelittin molecule are also found to bind and insert into the body of the phospholipid membrane, although nearly 30 times less rapidly than melittin. No charged sections of promelittin are found to insert into the membrane.

Original languageAmerican English
Pages (from-to)221-227
Number of pages7
JournalMolecular Membrane Biology
Volume15
Issue number4
DOIs
Publication statusPublished - 1998

Keywords

  • Electrostatic potential
  • Hydrophobic interaction
  • Presequence
  • Proline
  • Surface charge
  • β-turn

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