Wang Limin, Colón Wilfredo
Rensselaer Polytechnic Institute, Department of Chemistry and Chemical Biology, 110 8th street, Troy, NY 12180, USA.
Biochem Biophys Res Commun. 2004 Apr 23;317(1):157-61. doi: 10.1016/j.bbrc.2004.03.027.
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.
血清淀粉样蛋白A（SAA）是一种小的载脂蛋白，它通过其N端与高密度脂蛋白（HDL）结合。小鼠同种型SAA2.2在溶液中形成六聚体，其N端被溶剂屏蔽。因此，尚不清楚SAA2.2六聚体如何与HDL结合。在本研究中，通过戊二醛交联和聚丙烯酰胺凝胶电泳研究了SAA2.2与小鼠HDL的结合。在20℃时，六聚体与HDL的结合不明显。然而，在25-30℃之间的温度下，SAA2.2变得不稳定，其单体形式与HDL结合。SAA2.2的结合并没有显著取代HDL颗粒中的载脂蛋白A-I。在37-45℃时，SAA2.2与HDL的结合较少，这表明其结合较弱且对生理和病理温度敏感，因此在体内可能受到其他因素的调节。
