Huber R, Schneider M, Mayr I, Römisch J, Paques E P
Max Planck Institut für Biochemie, Martinsried, FRG.
FEBS Lett. 1990 Nov 26;275(1-2):15-21. doi: 10.1016/0014-5793(90)81428-q.
Crystal structure analysis and refinement at 2.0 A resolution of a rhombohedral crystal form of human annexin V at high calcium concentration revealed a domain motion compared to the previously analysed hexagonal crystal form. Five calcium ions were located on the convex face of the molecule. Three strongly bound calciums are liganded at protruding interhelical loops and Asp or Glu residues in homologous positions in repeats I, II and IV. Five proteinaceous oxygens and one solvent molecule form the coordination polyhedron in each case. The unoccupied seventh site is suggested as the phospholipid headgroup binding site. Two more weakly bound sites were identified by lanthanum labelling. The structural features suggest that annexin V attaches with its convex face to membranes by specific calcium mediated interactions with at least three phospholipids. The adjacent membrane bilayer may thus become locally disordered and permeable to allow calcium inflow through the central polar channel of the molecule.
在高钙浓度下对人膜联蛋白V的菱面体晶型进行2.0埃分辨率的晶体结构分析和精修，结果显示与之前分析的六方晶型相比存在结构域运动。五个钙离子位于分子的凸面上。三个紧密结合的钙离子与重复序列I、II和IV中同源位置的突出螺旋间环以及天冬氨酸或谷氨酸残基配位。在每种情况下，五个蛋白质氧原子和一个溶剂分子形成配位多面体。未占据的第七个位点被认为是磷脂头部基团结合位点。通过镧标记鉴定出另外两个弱结合位点。这些结构特征表明，膜联蛋白V通过与至少三种磷脂的特定钙介导相互作用，以其凸面附着于膜上。相邻的膜双层可能因此局部无序且具有通透性，以允许钙通过分子的中央极性通道流入。
