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A synthetic peptide's arginine swap cuts the dose needed to block Lp(a) assembly eight-fold, a structural study (J Lipid Res 2004)
Original title: Structural features of apolipoprotein B synthetic peptides that inhibit lipoprotein(a) assembly
This study examined the structural features of a synthetic apoB peptide (spanning amino acids 4372-4392) that inhibits Lp(a) assembly by disrupting apoB-apo(a) binding. A central leucine-to-proline substitution destroyed the peptide alpha-helical structure and abolished its inhibitory activity, while substituting hydrophobic residues disrupted inhibition without affecting the helical structure, showing both are needed. Replacing all four lysine residues with arginine reduced the IC50 from 40 microM to 5 microM, and complexing this arginine-substituted peptide with dimyristoylphosphatidylcholine further improved potency to an IC50 of 1 microM. The findings show the peptide alpha-helical structure combined with hydrophobic lipid-interface residues is crucial for apo(a) binding, and that arginine substitution, rather than requiring lysine specifically, produces a more effective Lp(a) assembly inhibitor.
Original abstract
Lipoprotein(a) [Lp(a)] is assembled via an initial noncovalent interaction between apolipoprotein B100 (apoB) and apolipoprotein(a) [apo(a)] that facilitates the formation of a disulfide bond between the two proteins. We previously reported that a lysine-rich, alpha-helical peptide spanning human apoB amino acids 4372-4392 was an effective inhibitor of Lp(a) assembly in vitro. To identify the important structural features required for inhibitory action, new variants of the apoB4372-4392 peptide were investigated. Introduction of a central leucine to proline substitution abolished the alpha-helical structure of the peptide and disrupted apo(a) binding and inhibition of Lp(a) formation. Substitution of hydrophobic residues in the apoB4372-4392 peptide disrupted apo(a) binding and inhibition of Lp(a) assembly without disrupting the alpha-helical structure. Substitution of all four lysine residues in the peptide with arginine decreased the IC50 from 40 microM to 5 microM . Complexing of the arginine-substituted peptide to dimyristoylphosphatidylcholine improved its activity further, yielding an IC50 of 1 microM. We conclude that the alpha-helical structure of apoB4372-4392, in combination with hydrophobic residues at the lipid/water interface, is crucial for its interaction with apo(a). Furthermore, the interaction of apoB4372-4392 with apo(a) is not lysine specific, because substitutions with arginine result in a more effective inhibitor.
Summary written by lp-a.org from the published abstract; figures as published. Page updated 18 August 2026. Methods.