Calcium-myristoyl protein switch.
Calcium-myristoyl protein switch.
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DOI：
10.1073/pnas.89.23.11569
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发表时间：
1992-12
影响因子：
11.1
通讯作者：
S. Zozulya;L. Stryer
中科院分区：
文献类型：
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作者：
S. Zozulya;L. Stryer
Recovery是最近发现的钙结合蛋白EF-手超家族成员，在视觉中作为钙传感器。来自视网膜杆细胞的蛋白质的氨基末端含有共价连接的肉豆蔻酰基或相关的N-酰基。我们在这里报告的研究unmyristoylated和myristoylated重组recoverin设计描绘这个疏水单位的生物学作用。Ca2+诱导未豆蔻酰化和豆蔻酰化的蛋白质与疏水支持物苯基琼脂糖结合。结合分别在1.1和1.0 μ M Ca2+时达到半最大值。希尔系数分别为1.8和1.7，表明结合是协同的。与此相反，钙离子诱导豆蔻酰化的结合，但不unmyristoylated恢复杆外段膜。与这些膜的结合在2.1 μ M Ca 2+时达到一半最大值，希尔系数为2.4。同样，豆蔻酰化的而不是非豆蔻酰化的recoverin表现出Ca（2+）诱导的磷脂酰胆碱囊泡结合。这些发现表明，Ca2+与recoverin的结合具有两种作用：（i）疏水表面暴露，允许蛋白质与互补的非极性位点相互作用，例如苯基琼脂糖的芳环;和（ii）肉豆蔻酰基被挤出，使recoverin能够插入脂质双层膜。肉豆蔻酰基可能是恢复素和相关EF-手蛋白（如visinin和neurocalcin）的Ca2+信号传导的积极参与者。
Recoverin, a recently discovered member of the EF-hand superfamily of Ca(2+)-binding proteins, serves as a Ca2+ sensor in vision. The amino terminus of the protein from retinal rod cells contains a covalently attached myristoyl or related N-acyl group. We report here studies of unmyristoylated and myristoylated recombinant recoverin designed to delineate the biological role of this hydrophobic unit. Ca2+ induces the binding of both the unmyristoylated and myristoylated proteins to phenyl-agarose, a hydrophobic support. Binding was half-maximal at 1.1 and 1.0 microM Ca2+, respectively. The Hill coefficients of 1.8 and 1.7, respectively, indicate that binding was cooperative. In contrast, Ca2+ induced the binding of myristoylated but not of unmyristoylated recoverin to rod outer segment membranes. Binding to these membranes was half-maximal at 2.1 microM Ca2+, and the Hill coefficient was 2.4. Likewise, myristoylated but not unmyristoylated recoverin exhibited Ca(2+)-induced binding to phosphatidylcholine vesicles. These findings suggest that the binding of Ca2+ to recoverin has two effects: (i) hydrophobic surfaces are exposed, allowing the protein to interact with complementary nonpolar sites, such as the aromatic rings of phenyl-agarose; and (ii) the myristoyl group is extruded, enabling recoverin to insert into a lipid bilayer membrane. The myristoyl group is likely to be an active participant in Ca2+ signaling by recoverin and related EF-hand proteins such as visinin and neurocalcin.