Apolipoprotein E: phospholipid binding studies with synthetic peptides from the carboxyl terminus
| Autor: | Doris A. Sparrow, Merry Kovar, James T. Sparrow, Germain J. P. Fernando, Alan R. Culwell, Antonio M. Gotto |
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| Rok vydání: | 1992 |
| Předmět: |
Apolipoprotein E
chemistry.chemical_classification Chemistry Stereochemistry Circular Dichroism Phospholipid Sequence (biology) Peptide Biochemistry Solvent chemistry.chemical_compound Apolipoproteins E Amphiphile Phospholipid Binding lipids (amino acids peptides and proteins) Amino Acid Sequence Binding site Dimyristoylphosphatidylcholine Peptides Protein Binding |
| Zdroj: | Biochemistry. 31(4) |
| ISSN: | 0006-2960 |
| Popis: | We have previously shown that the synthetic peptide apoE(129-169) forms lipid-peptide complexes with dimyristoylphosphatidylcholine (DMPC) with an L:P molar ratio of 125:1; the peptide in the isolated complex contains approximately 56% alpha-helicity. These results verify the presence of an amphipathic alpha-helix in this region of apoE as predicted by Chou-Fasman analysis and hydrophobicity calculations. To further define the lipid binding regions of apoE, we have synthesized four peptides, apoE(211-243), -(202-243), -(267-286), and -(263-286), from the carboxyl terminus of apoE and studied their lipid binding properties; apoE(202-243) contains two potential amphipathic helices. Although all four peptides formed alpha-helices in the helix-forming solvent 30% hexafluoropropanol, we found that only apoE(263-286) formed a stable complex with DMPC. The peptide contained approximately 80% alpha-helicity, and its Trp fluorescence spectrum was blue-shifted by 20 nm in the complex which had an L:P ratio of 163:1. We conclude that this sequence is a newly identified lipid binding region of apoE and that the amphipathic helices 203-221 and 226-243 are too hydrophilic to bind phospholipid. |
| Databáze: | OpenAIRE |
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