If space is provided, bulky modification on the rim of azurin's beta-barrel results in folded protein.
If space is provided, bulky modification on the rim of azurin's beta-barrel results in folded protein.
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如果提供空间，天青蛋白β-桶边缘的大量修饰会导致蛋白质折叠。
DOI：
10.1016/s0014-5793(02)03505-6
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发表时间：
2002
期刊：
影响因子：
3.5
通讯作者：
Wittung-Stafshede,Pernilla
中科院分区：
文献类型：
--
作者：
Pozdnyakova,Irina;Wittung-Stafshede,Pernilla
铜绿假单胞菌是一种具有β桶状折叠的蓝铜蛋白。在此，我们报道了在载蓝蛋白热展开可逆的条件下，反应发生在一个过渡中点（Tm）为69°C （pH 7）的单步反应中。活性位点突变His117Gly在β -桶表面附近产生一个空腔，但不会扰乱整体折叠（温度为64°C， pH为7）。野生型蓝蛋白中的活性位点半胱氨酸（半胱氨酸- 112）在较高温度下容易发生氧化，导致修饰蛋白不能采用天然样结构。与此形成鲜明对比的是，半胱氨酸- 112氧化His117Gly azurin产生修饰的apo - azurin，该apo - azurin看起来折叠并显示出合作的、可逆的展开（Tm ~ 55°C, pH 7）。我们得出结论：azurin的β -桶是一种刚性结构元件，约束了其表面结构；只有在提供补充空间的情况下，才能容纳庞大的修改。
Pseudomonas aeruginosaazurin is a blue‐copper protein with a β‐barrel fold. Here we report that, at conditions where thermal unfolding of apo‐azurin isreversible, the reaction occurs in a single step with a transition midpoint (Tm) of 69°C (pH 7). The active‐site mutation His117Gly creates a cavity in the β‐barrel near the surface but does not perturb the overall fold (Tmof 64°C, pH 7). Oxidation of the active‐site cysteine (Cysteine‐112) in wild‐type azurin, which occurs readily at higher temperatures, results in a modified protein that cannot adopt a native‐like structure. In sharp contrast, Cysteine‐112 oxidation in His117Gly azurin yields a modified apo‐azurin that appears folded and displays cooperative, reversible unfolding (Tm∼55°C, pH 7). We conclude that azurin's β‐barrel is a rigid structural element that constrains the structure of its surface; a bulky modification can only be accommodated if complementary space is provided.