Restricted mobility of the sole tryptophan in membrane-bound melittin.
In spite of numerous studies, there appears to be no consensus regarding the orientation and aggregation state of membrane-bound melittin. We report here the restricted environment of the sole tryptophan residue in membrane-bound melittin using environment-induced effects on the rates of solvent relaxation. When incorporated into unilamellar vesicles of dioleoyl-sn-glycero-3-phosphocholine (DOPC), melittin exhibits a red edge excitation shift (REES) of 5 nm. In addition, fluorescence polarization of melittin in the membrane shows both excitation and emission wavelength dependence. Taken together, these observations indicate that the tryptophan residue of melittin is located in a motionally restricted region in the membrane.
Chattopadhyay
A
A
Centre for Cellular and Molecular Biology, Hyderabad, India.
Rukmini
R
R
D000818:Animals; D005454:Fluorescence Polarization; D008051:Lipid Bilayers / Q000378:metabolism*; D008555:Melitten / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism*
D008051:Lipid Bilayers; D008555:Melitten; D014364:Tryptophan