title: Retention of α-helical structure by HDL mimetic peptide ATI-5261 upon extensive dilution represents an important determinant for stimulating ABCA1 cholesterol efflux with high efficiency.
abstract: ATI-5261 is a novel, single-helix peptide that stimulates cellular cholesterol efflux with high potency similar to native apolipoproteins on a molar basis. Presently we investigated structural features of the peptide that conferred cholesterol efflux activity. Analogs of ATI-5261 with amino acids arranged in reverse order or with individual arginine (R) to glutamine (Q) substitutions (i.e. R3Q, R14Q, or R23Q) stimulated ABCA1 dependent cholesterol efflux similar to ATI-5261. Consequently, neither the presence of specific positively charged residues nor their specific arrangement along the length of the peptide was necessary for mediating cholesterol efflux. Similarly, peptides composed of all d-amino acids stimulated cholesterol efflux efficiently, indicating a stereospecific component was not required for promotion of cholesterol efflux from macrophages. Removal of two or more positively charged residues (R3, 14→Q and R3, 14, 23→Q) however, greatly reduced the ability of ATI-5261 to mediate cellular cholesterol efflux. This was accompanied by a loss of α-helical structure upon dilution, indicating the secondary structure of individual peptide strands was important for stimulating cholesterol efflux. Surprisingly, peptides with removal of two or more positively charged residues retained the ability to bind phospholipid and adopt an α-helical structure. These data indicate that the propensity of a hydrophobic peptide to form an amphipathic α-helix is not sufficient to mediate cellular cholesterol efflux. Efficient stimulation of cholesterol efflux requires that ATI-5261 retain α-helical structure upon dilution.
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Donner Laboratory, University of California, Berkeley, CA 94720, United States.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Arti B
authors.initials: AB
authors.lastname: Patel
authors.forename: Vasanthy
authors.initials: V
authors.lastname: Narayanaswami
authors.forename: John K
authors.initials: JK
authors.lastname: Bielicki
mesh_terms: D064286:ATP Binding Cassette Transporter 1 / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D055592:Biophysical Phenomena; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism*; D004134:Dimyristoylphosphatidylcholine; D036341:Intercellular Signaling Peptides and Proteins; D050356:Lipid Metabolism; D008075:Lipoproteins, HDL / Q000737:chemistry* / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
chemical_list: D064286:ATP Binding Cassette Transporter 1; D002784:Cholesterol; D004134:Dimyristoylphosphatidylcholine; D036341:Intercellular Signaling Peptides and Proteins; D008075:Lipoproteins, HDL; D010455:Peptides; C577833:Abca1 protein, mouse; C585585:ATI-5261
keywords: Atherosclerosis; Cholesterol efflux; HDL mimetic peptides; Macrophages; Reverse cholesterol transport; Therapeutic peptides; α-Helix