sodium-dodecyl-sulfate and lysophosphatidylglycerol

The frequent occurrence of beta-sheet promoting residues such as Ile, Val, and Thr in the alpha-helical transmembrane segments of most integral membrane proteins suggests that the helical propensities of these residues are altered in the hydrophobic environment of the lipid bilayer. Systematic studies of model peptides by circular dichroism models spectroscopy in various micellar/vesicular media allow the establishment of a ranking order of helical propensity for uncharged amino acids in the membrane environment. In contrast to their conformational preferences in water, the helical proclivity of amino acids in membranes is shown to be governed by their side chain hydrophobicity, and by the hydropathy of the local peptide segments in which the residues reside [corrected].

Topics: Amino Acid Sequence; Amino Acids; Chemical Phenomena; Chemistry, Physical; Circular Dichroism; Lipid Bilayers; Lysophospholipids; Membrane Lipids; Membrane Proteins; Micelles; Molecular Sequence Data; Peptides; Phosphatidylglycerols; Protein Conformation; Protein Structure, Secondary; Sodium Dodecyl Sulfate

The accumulation of lysophosphoglycerides has been implicated as an important biochemical factor for cardiac arrhythmias. Recently, we demonstrated that lysophosphatidylcholine caused cardiac arrhythmias in the isolated hamster heart. In this study, the arrhythmogenic nature of various lysophosphoglycerides with respect to acyl chain lengths and base groups were assessed. We demonstrated that all naturally occurring lysolipids tested were arrhythmogenic at 0.05-0.10 mM. Arrhythmias were also observed with Triton X-100 or sodium laurylsulfate at 0.05-0.10 mM. Our data suggests that no correlation exists between the arrhythmogenic nature of the lysolipids and their critical micelle concentrations. We postulate that arrhythmias are produced by the detergent effect of lysophosphoglycerides.

Topics: Animals; Arrhythmias, Cardiac; Cricetinae; Glycerophosphates; Lysophosphatidylcholines; Lysophospholipids; Mesocricetus; Octoxynol; Phosphatidylethanolamines; Phosphatidylglycerols; Phosphatidylserines; Polyethylene Glycols; Sodium Dodecyl Sulfate; Structure-Activity Relationship