Identification of the phospholipid binding site in the vitamin K-dependent blood coagulation protein factor IX
Identification of the phospholipid binding site in the vitamin K-dependent blood coagulation protein factor IX
复制标题
DOI：
10.1074/jbc.271.27.16227
复制
发表时间：
1996-07-05
影响因子：
4.8
通讯作者：
Furie, B
中科院分区：
文献类型：
--
作者：
Freedman, SJ;Blostein, MD;Furie, B
含有γ-羧基谷氨酸的血液凝固和调节蛋白是一类独特的膜结合蛋白的一部分，其需要钙与细胞膜相互作用。在蛋白质生物合成后，这些蛋白质上的谷氨酸在需要维生素K作为辅因子的反应中转化为γ-羧基谷氨酸（Gla）。维生素K依赖性蛋白质在金属离子结合时经历构象转变，但只有钙离子介导蛋白质-磷脂相互作用。为了鉴定磷脂结合所需的因子IX上的位点，我们已经通过NMR光谱确定了与镁离子结合的因子IX Gla结构域的三维结构。通过将该结构与与钙离子结合的Gla结构域的结构进行比较，我们将膜结合位点定位于包括Gla结构域的残基1-11的高度有序的结构。在位置6或9处含有可光活化的氨基酸对苯甲酰基-L-苯丙氨酸的因子IX Gla结构域肽在照射后与磷脂交联，而缺乏该氨基酸类似物或在位置46处具有该类似物的肽不交联。这些结果表明，Gla结构域的NH 2末端，特别是在疏水补丁中包括亮氨酸6和苯丙氨酸9，是与磷脂双层相互作用的因子IX上的接触表面。
The blood coagulation and regulatory proteins that contain gamma-carboxyglutamic acid are a part of a unique class of membrane binding proteins that require calcium for their interaction with cell membranes. Following protein biosynthesis, glutamic acids on these proteins are converted to gamma-carboxyglutamic acid (Gla) in a reaction that requires vitamin K as a cofactor, The vitamin K-dependent proteins undergo a conformational transition upon metal ion binding, but only calcium ions mediate protein-phospholipid interaction. To identify the site on Factor IX that is required for phospholipid binding, we have determined the three-dimensional structure of the Factor IX Gla domain bound to magnesium ions by NMR spectroscopy, By comparison of this structure to that of the Gla domain bound to calcium ions, we localize the membrane binding site to a highly ordered structure including residues 1-11 of the Gla domain, In the presence of Ca2+, Factor IX Gla domain peptides that contain the photoactivatable amino acid p-benzoyl-L-phenylalanine at positions 6 or 9 cross-link to phospholipid following irradiation, while peptides lacking this amino acid analog or with this analog at position 46 did not cross-link. These results indicate that the NH2 terminus of the Gla domain, specifically including leucine 6 and phenylalanine 9 in the hydrophobic patch, is the contact surface on Factor IX that interacts with the phospholipid bilayer.