The effect of membranes on the conformation of neuromedin C.

The 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 state.