The interaction between apolipoprotein serum amyloid A and high-density lipoprotein.
Serum amyloid A (SAA) is a small apolipoprotein that binds to high-density lipoproteins (HDLs) via its N-terminus. The murine isoform SAA2.2 forms a hexamer in solution and the N-terminus is shielded from the solvent. Therefore, it is unclear how the SAA2.2 hexamer might bind HDL. In this study, the binding of SAA2.2 to murine HDL was investigated by glutaraldehyde cross-linking and polyacrylamide gel electrophoresis. The hexamer did not bind HDL significantly at 20 degrees C. However, at temperatures between 25-30 degrees C, SAA2.2 became destabilized and its monomeric form bound to HDL. SAA2.2 binding did not significantly replace Apo A-I in HDL particles. At 37-45 degrees C SAA2.2 binds less to HDL, suggesting that its binding is weak and sensitive to physiological and pathological temperatures, and thereby, potentially modulated, in vivo, by other factors.
Wang
Limin
L
Rensselaer Polytechnic Institute, Department of Chemistry and Chemical Biology, 110 8th street, Troy, NY 12180, USA.
Colón
Wilfredo
W
D000595:Amino Acid Sequence; D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods; D003432:Cross-Linking Reagents / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005976:Glutaral / Q000737:chemistry; D008075:Lipoproteins, HDL / Q000097:blood*; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000685:Serum Amyloid A Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D003432:Cross-Linking Reagents; D008075:Lipoproteins, HDL; D011994:Recombinant Proteins; D000685:Serum Amyloid A Protein; D005976:Glutaral