The structure of human apolipoprotein E2, E3 and E4 in solution 1. Tertiary and quaternary structure.

摘要: Three recombinant apoE isoforms fused with an amino-terminal extension of 43 amino acids were produced in a heterologous expression system E. coli. Their state association aqueous phase was analyzed by size-exclusion liquid chromatography, sedimentation velocity and equilibrium experiments. By all three consisted major species Stokes radii 4.0, 5.0 6.6 nm. Sedimentation confirmed the presence monomers, dimers tetramers as each isoform. The schemes established experiments corresponded to monomer–dimer–tetramer–octamer for apoE2, monomer–dimer–tetramer apoE3 apoE4. Each exhibits distinct self-association pattern. apolipoprotein multi-domain structure mapped limited proteolysis trypsin, chymotrypsin, elastase, subtilisin Staphylococcus aureus V8 protease. All five enzymes stable intermediates during degradation isoforms, described plasma apoE3. thus, consist N- C-terminal domains. fusion peptide did not appear alter tertiary organization. However, 30 kDa fragment appeared resulting from cleavage 273–278 region. This region, accessible apoE3, results different conformation domain isoforms. A specific pattern apoE4 observed proteolysis. region 230–260 apoE4, contrast that proteases, probably due existence longer helix this stabilized interdomain interaction.