Fluorescence depolarization of the exposed tryptophanyl residue in the peptide melittin and the buried tryptophanyl residue in the protein azurin (from the bacteria Pseudomonos aeruginoso) was measured with subpicosecond resolution at various excitation and emission wavelengths. A short time component was found in both the fluorescence decay and fluorescence anisotropy decay for the tryptophany...

The in vivo application of cytolytic peptides for cancer therapeutics is hampered by toxicity, nonspecificity, and degradation. We previously developed a specific strategy to synthesize a nanoscale delivery vehicle for cytolytic peptides by incorporating the nonspecific amphipathic cytolytic peptide melittin into the outer lipid monolayer of a perfluorocarbon nanoparticle. Here, we have demonst...

Cobra snake venom cardiotoxins and bee venom melittin share a number of pharmacological properties in intact tissues including hemolysis, cytolysis, contractures of muscle, membrane depolarization and activation of tissue phospholipase C and, to a far lesser extent, an arachidonic acid-associated phospholipase A2. The toxins have also been demonstrated to open the Ca2+ release channel (ryanodin...

The molecular mechanism by which HFIP stabilizes the alpha-helical structure of peptides is not well understood. In the present study, we use melittin as a model to gain insight into the details of the atomistic interactions of HFIP with the peptide. We have performed extensive comparative molecular dynamics simulations (up to 100 nsec) in the absence and in the presence of HFIP. In agreement w...

the interaction between proteins and membranes has an important role in biological pro-cesses.we have calculated energies of interaction between melittin and dmpc bilayer in differenttemperatures. we have used the charmm software for md simulation under the canonical (n,v, e) ensemble at different temperatures. the computations have shown that water moleculeshave more penetration into the bilay...

Phospholipase A(2) (PLA(2)) activation enhances glutamatergic excitatory synaptic transmission in substantia gelatinosa (SG) neurons, which play a pivotal role in regulating nociceptive transmission in the spinal cord. By using melittin as a tool to activate PLA(2), we examined the effect of PLA(2) activation on spontaneous inhibitory postsynaptic currents (sIPSCs) recorded at 0 mV in SG neuron...

Melittin, an amphipathic peptide from honeybee venom, consists of 26 amino acid residues and adopts different conformations from a random coil, to an alpha-helix, and to a self-assembled tetramer under certain aqueous environments. We report here our systematic studies of the hydration dynamics in these conformations using single intrinsic tryptophan (W19) as a molecular probe. With femtosecond...

To better understand the sequence-structure-function relationships that control the activity and selectivity of membrane-permeabilizing peptides, we screened a peptide library, based on the archetypal pore-former melittin, for loss-of-function variants. This was accomplished by assaying library members for failure to cause leakage of entrapped contents from synthetic lipid vesicles at a peptide...

Electron capture dissociation (ECD) has been proposed to be a non-ergodic process, i.e. to provide backbone dissociation of gas-phase peptides faster than randomization of the imparted energy. One potential consequence could be that ECD can fragment deuterated peptides without causing hydrogen scrambling and thereby provide amino acid residue-specific amide hydrogen exchange rates. Such a featu...

The interaction of melittin, the major protein component of bee venom, with dimyristoyl phosphatidylcholine ( DMPC ) liposomes was investigated by Electron Spin Resonance (ESR) spectroscopy using high resolution amphiphilic spin probe perdeutero-di-t-butyl nitroxide (PDDTBN). For pure DMPC liposomes, ESR signal due to the probe dissolved in the fluid hydrophobic environment provided by the inte...