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Conformational changes of neuromedin B and delta sleep-inducing peptide induced by their interaction with lipid membranes as revealed by spectroscopic techniques and molecular dynamics simulation.
No full textStatic and dynamic spectroscopic properties of the tryptophanil emission in conjunction with circular dichroism (CD) spectroscopy and molecular dynamics are used to investigate the interactions of the neuropeptide neuromedin B (NMB) and the membrane-permeable δ sleep-inducing peptide (DSIP) with the membrane lipid phase. Our data indicate that in solution both peptides exist in energetically equivalent conformations, whereas in the presence of the membrane specific conformational states are stabilized. By changing from the aqueous to the lipid phase, the static and the dynamic fluorescence properties of the NMB's tryptophan residue are clearly affected: the fluorescence steady-state spectrum as well as the resolved fluorescence decay-associated spectra (DAS) are shifted to the blue with a significant increase of the fluorescence intensity of the second lifetime component (τ2-DAS). On the other hand, in the lipid environment the same parameters of DSIP are negligibly affected as compared to the aqueous buffer. The CD and molecular dynamics analyses are consistent with these results and indicate that, while NMB assumes a helix-like conformation with the tryptophan residue in the apolar surface, DSIP adopts a globule-like structure with the indole ring that is surface-exposed. As previously found for neuromedin C (Polverini, E., Neyroz, P., Fariselli, P., Casadio, R., and Masotti, L., Biochem. Biophys. Res. Commun. 214, 663-668, 1995), for NMB the stabilized 'lipophilic' structure also may favor the correct peptide-receptor contact and recognition. For DSIP, the lipid-stabilized conformation does not support an amphiphilic structure-driven peptide-membrane interaction and suggests a hydrophobicity-driven diffusion across the bilayer
Time resolved fluorescence studies of small neuropeptides: clues for their membrane interaction modes.
No full textTimeresolved fluorescence studies of single-tryptophan containing neuropeptides: evidence of the rotamer model
No full textSteady-State and Time Resolved Characterization of a New Fluorescent Phospholipid to Study the Excited-State Proton Transfer Processes at the Membrane Surface
No full text2-Naphthol-Phosphatidylethanolamine: A Fluorescent Phospholipid Analogue for Excited-State Proton Transfer Studies in Membranes
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The effect of membranes on the conformation of neuromedin C
No full textThe combination of static and dynamic spectroscopy data with the information obtained by computational methods has been used to investigate the conformation of neuromedin C in the absence and in the presence of lipid membranes. Upon addition of lipids, the peptide steady-state emission spectrum is blue shifted (355 nm vs 345 nm) and all the recovered fluorescence decay constants are significantly longer. CD measurements show that fluorescence changes are consistent with alpha-helix inducing structural transitions. Molecular dynamics studies show that, in solution, the peptide conformation rapidly exchanges between energetically equivalent disordered and ordered states, whereas, in the presence of membrane, the peptide conformation is stabilized in an ordered stat
Interaction of small neuropeptides with the membrane phase: spectroscopic and computational studies.
No full textThe different peptide-lipid membrane interaction of neuromedin B (NMB) and delta-sleep inducing peptide (DSIP) as revealed by spectroscopic techniques and molecular simulation.
No full textBinding of synapsin i to synaptic vesicles: Clues from the study of its interactions with liposomes
No full textSynapsin I is a major brain phosphoprotein which interacts with synaptic vesicles and actin in a phosphorylation-dependent fashion. The binding of synapsin I to synaptic vesicles involves interactions with the phospholipid and protein components of the vesicle membrane. The highly hydrophobic NH2-terminal head region of the protein binds with high-affinity to acidic phospholipids and penetrates the hydrophobic core of the membrane, whereas the basic COOH-terminal tail region does not significantly contribute to this binding. The interaction with phospholipids increases the amount of αhelix in the secondary structure of synapsin I, but does not markedly affect the microenvironment of tryptophan and cysteine residues present in the head region. The results suggest that synapsin I binds to synaptic vesicle phospholipids through amphiphilic and positively charged domains present in its NH2-terminal region and that such an interaction contributes to the high-affinity binding of synapsin I to synaptic vesicles. © 1993 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted
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