Human apolipoprotein E3 in aqueous solution. II. Properties of the amino- and carboxyl-terminal domains.

摘要: Hydrodynamic, chromatographic, and spectroscopic techniques were used to study the aqueous solution properties of two structural domains human apolipoprotein (apo) E3. An amino-terminal thrombolytic fragment apoE (22 kDa, residues 1-191) a carboxyl-terminal (10 216-299) as models for domains. Sedimentation equilibrium ultracentrifugation showed that 10-kDa model domain self-associated predominantly tetramers. The 22-kDa was primarily monomeric. Molecular weights calculated from weight average sedimentation diffusion coefficients or Stokes radii in agreement with results. Derived frictional suggest larger axial ratios and/or more extensive hydration tetramers compared domain. Proteolysis followed by high performance liquid chromatography rapid production free domain, whereas appeared tetramer late course hydrolysis. Assessment circular dichroism demonstrated both had over 54% alpha-helical content, which changed little detergent (octyl-beta-D-glucopyranoside) lipid (dimyristoylphosphatidylcholine) environment. In contrast results, marked blue shift fluorescence maximum results self-association is mediated amino- do not associate one another. most likely compact globular, probably elongated. isolated appear have structures are similar those intact protein.