Allosteric modulation of caspase 3 through mutagenesis.
Allosteric modulation of caspase 3 through mutagenesis.
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DOI：
10.1042/bsr20120037
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发表时间：
2012-08
影响因子：
4
通讯作者：
Clark AC
中科院分区：
文献类型：
--
作者：
Walters J;Schipper JL;Swartz P;Mattos C;Clark AC
Val 266与组氨酸的半胱天冬酶3二聚体界面的变构位点的突变消除了酶的活性，并且模型预测该突变通过阻止活性位点的形成来模拟小分子变构抑制剂的作用。突变在界面中的两个位点E124A和Y197C与His266偶联。我们目前的结果，从X射线晶体学，酶活性和分子动力学模拟七种蛋白质，包括单，双和三重突变体。结果表明，认为胱天蛋白酶3的变构抑制离散的“关状态”或“开状态”构象之间的转变是不够的。尽管His266被容纳在界面中，但结构缺陷通过蛋白质表面上的螺旋传播到活性位点。一个更全面的看法，caspase 3的变构调节需要代表的合奏的非活性状态，并表明，微妙的结构变化导致人口的非活性合奏。
A mutation in the allosteric site of the caspase 3 dimer interface of Val266 to histidine abolishes activity of the enzyme, and models predict that the mutation mimics the action of small molecule allosteric inhibitors by preventing formation of the active site. Mutations were coupled to His266 at two sites in the interface, E124A and Y197C. We present results from X-ray crystallography, enzymatic activity and molecular dynamics simulations for seven proteins, consisting of single, double and triple mutants. The results demonstrate that considering allosteric inhibition of caspase 3 as a shift between discrete ‘off-state’ or ‘on-state’ conformations is insufficient. Although His266 is accommodated in the interface, the structural defects are propagated to the active site through a helix on the protein surface. A more comprehensive view of allosteric regulation of caspase 3 requires the representation of an ensemble of inactive states and shows that subtle structural changes lead to the population of the inactive ensemble.