CRYSTAL STRUCTURE OF HUMAN APOLIPOPROTEIN I

载脂蛋白A-I（apoA-I）是人外周血中的主要蛋白质成分， 人高密度脂蛋白（HDL）。 血液中高密度脂蛋白水平 与动脉粥样硬化风险降低密切相关，因此 降低冠状动脉疾病的风险。 所有的选民 只有apo A-I与HDL的这种保护作用相关。 我们已经结晶了载脂蛋白A-I的44-243位残基， 与完整的载脂蛋白A-I类似， 甚至在没有脂质的情况下也是如此。 该分子由 几乎完全是假连续的两亲性α-螺旋， 在规则间隔的脯氨酸残基处被扭结打断;它采用了一种 形状类似于尺寸为125 x 80 x 40 E的马蹄铁。四 不对称单元中的分子通过它们的疏水面缔合 以形成具有椭圆环形状的反平行4螺旋束。 基于这种结构，我们提出了一个apo结构模型 我和HDL结合了

Apolipoprotein A-I (apo A-I) is the major protein component of human high-density lipoprotein (HDL). High blood levels of HDL strongly correlate with a reduced risk of atherosclerosis, and hence a reduced risk of coronary artery disease. Of all of the constituents of HDL, only apo A-I correlates with this protective effect of HDL. We have crystallized residues 44-243 of apo A-I, a fragment that binds to lipid similarly to intact apo A-I and that retains the lipid-bound conformation even in the absence of lipid. The molecule consists almost entirely of a pseudo-continuous amphipathic alpha-helix that is punctuated by kinks at regularly-spaced proline residues; it adopts a shape similar to a horseshoe of dimensions 125 x 80 x 40 E. Four molecules in the asymmetric unit associate via their hydrophobic faces to form an antiparallel 4-helix bundle with an elliptical ring shape. Based on this structure, we propose a model for the structure of apo A-I bound to HDL.