Interfacial properties of amphipathic beta strand consensus peptides of apolipoprotein B at oil/water interfaces.
The region between residues 968 and 1882 of apolipoprotein B (apoB-21 to apoB-41) is rich in amphipathic beta strands (AbetaSs) and promotes the assembly of primordial triacylglyceride (TAG)-rich lipoproteins. To understand the importance of AbetaS in recruiting TAG, the interfacial properties of two AbetaS consensus peptides, P12 and P27, were studied at dodecane/water (DD/W) and triolein/water (TO/W) interfaces. P12 (acetyl-LSLSLNADLRLK-amide) and P27 (acetyl-LSLSLNADLRLKNGNLSLSLNADLRLK-amide), when added into the aqueous phase surrounding a suspended oil drop (dodecane or triolein), decreased the interfacial tension (gamma) in a concentration-dependent manner. At the DD/W interface, 1 x 10(-5) M P12 decreased gamma to approximately 20 mN/m and 6.6 x 10(-6) M P27 decreased gamma to approximately 13 mN/m. At the TO/W interface, 1.5 x 10(-5) M P12 decreased gamma to approximately 14 mN/m and 9.0 x 10(-6) M P27 decreased gamma to approximately 12 mN/m. The surface area of both peptides was between 11.2 and 15.1 angstroms2 per residue, consistent with beta sheets lying flat on DD/W and TO/W interfaces. P12 and P27 are almost purely elastic on DD/W, TO/W, and air/water interfaces. When P12 and P27 were compressed beyond the equilibrium gamma to as low as 4 mN/m, they could not be readily desorbed from either interface. These properties probably help in assembling nascent TAG-rich lipoproteins, and AbetaS may anchor apoB to beta lipoproteins.
Wang
Libo
L
Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118.
Small
Donald M
DM
D000327:Adsorption; D000473:Alkanes / Q000737:chemistry; D000595:Amino Acid Sequence; D001055:Apolipoproteins B / Q000737:chemistry*; D016384:Consensus Sequence; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D013500:Surface Tension; D013997:Time Factors; D014304:Triolein / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D000473:Alkanes; D001055:Apolipoproteins B; D010455:Peptides; D014867:Water; C007548:n-dodecane; D014304:Triolein