Activation of lecithin:cholesterol acyltransferase by a synthetic model lipid-associating peptide.

H. J. Pownall, A. Hu, A. M. Gotto, J. J. Albers, J. T. Sparrow

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Abstract

We have synthesized a model lipid-associating peptide of 20 residues (LAP-20) and studied its association with the phospholipid dimyristoyl phosphatidylcholine (DMPC) and its activation of the plasma enzyme lecithin:cholesterol acyl-transferase (EC 2.3.1.43). The lipid-associating behavior of LAP-20 is similar to that of well-characterized native plasma apolipoproteins after which it was modeled. Upon forming an isolated complex with DMPC, LAP-20 exhibits a large blue-shift in its intrinsic fluorescence, converts from a random coil to an alpha -helix, and changes turbid multilamellar structures of DMPC into small complexes that are optically clear. Addition of 2 mol % cholesterol does not detectably alter the structure or properties of the complex. The cholesterol-containing complexes of LAP-20 and DMPC are substrates for LCAT, having an activity 65% of that of complexes composed of DMPC, cholesterol, and the natural activator, apolipoprotein A-I. These findings suggest that the LCAT-activating regions of apoA-I may be confined to relatively short sequences that contain a lipid-binding determinant.

Original languageEnglish (US)
Pages (from-to)3154-3158
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume77
Issue number6
DOIs
StatePublished - Jun 1980

ASJC Scopus subject areas

  • General

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