title: Structural and functional characterization of human apolipoprotein E 72-166 peptides in both aqueous and lipid environments.
abstract: BACKGROUND
  There are three apolipoprotein E (apoE) isoforms involved in human lipid homeostasis. In the present study, truncated apoE2-, apoE3- and apoE4-(72-166) peptides that are tailored to lack domain interactions are expressed and elucidated the structural and functional consequences.
  
  
  RESULTS
  Circular dichroism analyses indicated that their secondary structure is still well organized. Analytical ultracentrifugation analyses demonstrated that apoE-(72-166) produces more complicated species in PBS. All three isoforms were significantly dissociated in the presence of dihexanoylphosphatidylcholine. Dimyristoylphosphatidylcholine turbidity clearance assay showed that apoE4-(72-166) maintains the highest lipid-binding capacity. Finally, only apoE4-(72-166) still maintained significant LDL receptor binding ability.
  
  
  CONCLUSIONS
  Overall, apoE4-(72-166) peptides displayed a higher lipid-binding and comparable receptor-binding ability as to full-length apoE. These findings provide the explanation of diverged functionality of truncated apoE isoforms.
authors.affiliation: Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan.
authors.forename: Yi-Hui
authors.initials: YH
authors.lastname: Hsieh
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Chou
mesh_terms: D001057:Apolipoproteins E / Q000737:chemistry* / Q000378:metabolism; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D010713:Phosphatidylcholines / Q000737:chemistry* / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D001057:Apolipoproteins E; D010455:Peptides; D010713:Phosphatidylcholines; D020033:Protein Isoforms; C032166:1,2-hexanoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine