Lipid membrane binding of NK-lysin.
The membrane-binding properties and pore-forming potential of the tumor-lysing and antibacterial polypeptide NK-lysin were investigated. Fluorescence quenching experiments show a drastic change of accessibility to Trp58 in solution and in association with a lipid membrane. Calcein release from large unilamellar vesicles and fluctuating conductivity observed across a planar lipid bilayer of asolectin show that NK-lysin renders lipid bilayers permeable in a transient fashion, indicating a nonspecific lipid interaction as the mechanism underlying the biological activity. FTIR experiments show the same amount and type of regular secondary structure of NK-lysin in the membrane as in aqueous solution and exclude a structural rearrangement into a set of parallel or antiparallel alpha-helices as the predominant conformation. The molecular mechanism of the membrane-destabilizing effect of NK-lysin is discussed.
Ruysschaert
J M
JM
Laboratoire de Chimie Physique des Macromolécules aux Interfaces, Université Libre de Bruxelles, Brussels, Belgium. jmruyss@ulb.ac.be
Goormaghtigh
E
E
Homblé
F
F
Andersson
M
M
Liepinsh
E
E
Otting
G
G
D000890:Anti-Infective Agents / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism*; D008958:Models, Molecular; D011510:Proteolipids / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism*
D000890:Anti-Infective Agents; D008051:Lipid Bilayers; C093238:NK-lysin; D011510:Proteolipids; D011663:Pulmonary Surfactants