Spectroscopic and AFM characterization of polypeptide-surface interactions: Controls and lipid quantitative analyses.

This article is related to http://dx.doi.org/10.

Peptides derived from α-lactalbumin membrane binding helices oligomerize in presence of lipids and disrupt bilayers.

Helix A and -C of α-lactalbumin, a loosely folded amphitropic protein, perturb lipid monolayers by the formation of amyloid pore-like structures. To investigate whether these helices are able to disrupt fully formed bilayers, we designed peptides comprised of Helix A and -C, and investigated their membrane-perturbing properties. The peptides, designated A-Cage-C and A-Lnk-C, were prepared with tryptophan sites in the helical and the spacer segments in order to monitor which part were involved in membrane association under given conditions.

α-Lactalbumin:Oleic Acid Complex Spontaneously Delivers Oleic Acid to Artificial and Erythrocyte Membranes.

Human α-lactalbumin made lethal to tumor cells (HAMLET) is a tumoricidal complex consisting of human α-lactalbumin and multiple oleic acids (OAs). OA has been shown to play a key role in the activity of HAMLET and its related complexes, generally known as protein-fatty acid (PFA) complexes. In contrast to what is known about the fate of the protein component of such complexes, information about what happens to OA during their action is still lacking.

Cytotoxicity of bovine α-lactalbumin: oleic acid complexes correlates with the disruption of lipid membranes.

HAMLET/BAMLET (Human/Bovine α-Lactalbumin Made Lethal to Tumors) is a tumoricidal substance composed of partially unfolded human/bovine α-lactalbumin (HLA/BLA) and several oleic acid (OA) molecules. The HAMLET mechanism of interaction involves an insufficiently understood effect on the membrane or its embedded components. We examined the effect of BLAOA (bovine α-lactalbumin complexed with oleic acid, a HAMLET-like substance) and its individual components on cells and artificial lipid membranes using viability staining and metabolic dyes, fluorescence spectroscopy, leakage integrity assays and microscopy.