Author/Editor		Majhenc, Janja; Svetina, Saša; Zorko, Matjaž; Žekš, Boštjan
Title		Lipid-polypeptide interactions studied by optical observation of a single giant lipid vesicle
Type		članek
Source		In: Pramanik A, editor. Biochemistry and biophysics of lipids 2006. Kerala: Transworld research network,
Vol. and No.		Letnik 37/661, št. 2
Publication year		2006
Volume		str. 132-152
Language		eng
Abstract		Lipid-polypeptide interactions play an important role in different cellular processes. One of the methods to study effect of different peptides and proteins on lipid bilayer is to observe a single giant lipid vesicle suspended in the solution of the respective polypeptide by an optical microscope thus revealing phenomena related to the different types of interactions of polypeptides with lipids. The advantage of the observation of a single giant vesicle in comparison to measurements on the population of small or large vesicles lays in the possibility of direct optical monitoring of vesicle morphology and its dynamics that could not be detected using vesicle population approach. In our review we deal with the preparation and manipulation of giant phospholipid vesicles, the observation methods using phase contrast microscopy and the analysis of the observed vesicle behavior. The results of these analyses are related to the processes of polypeptide binding to membrane surface, penetration into the membrane core and possible release into the vesicle interior. A special emphasis is in the formation of membrane pores by polypeptides and consequent osmotic behavior of the system. This is illustrated by two example polypeptides, a pore forming protein equinatoxin II and a cell-penetrating peptide transportan.
Descriptors		MEMBRANE LIPIDS PEPTIDES PROTEIN BINDING PHOSPHOLIPIDS MEMBRANE FLUIDITY LIPID BILAYERS SUCROSE GLUCOSE OSMOSIS MICROSCOPY, PHASE-CONTRAST DENSITOMETRY CALIBRATION MODELS, THEORETICAL