Energetic landscape of α-lytic protease optimizes longevity through kinetic stability
Energetic landscape of α-lytic protease optimizes longevity through kinetic stability
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DOI：
10.1038/415343a
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发表时间：
2002-01-17
期刊：
影响因子：
64.8
通讯作者：
Agard, DA
中科院分区：
文献类型：
--
作者：
Jaswal, SS;Sohl, JL;Agard, DA
在蛋白质的进化过程中，优化生物活性的压力因有效折叠的需要而减轻。对于大多数蛋白质来说，这是通过自发折叠成热力学稳定且活跃的天然状态来实现的。然而，在细胞外细菌α-裂解蛋白酶（alphaLP）中，这两个过程已经分离。 αLP 的天然状态在热力学上不稳定，当变性时，需要数千年（t(1/2)，类似于 1,800 年）(1) 才能重新折叠。折叠是通过附着的折叠催化剂（即前区）实现的，该催化剂在折叠完成后会降解，使 alphaLP 被大的动力学展开屏障困在其天然状态（t(1/2) 类似于 1.2 年）(1)。 alphaLP 面临两种截然不同的折叠景观：一种是存在控制折叠的亲区域，另一种是不存在限制展开的情况。在这里，我们证明折叠和解折叠途径的这种分离消除了对热力学稳定蛋白质折叠的限制，并允许自然状态的进化，从而显着减少动态波动。这反过来又通过优化蛋白水解敏感性的抑制，显着延长了 alphaLP 的功能寿命。
During the evolution of proteins the pressure to optimize biological activity is moderated by a need for efficient folding. For most proteins, this is accomplished through spontaneous folding to a thermodynamically stable and active native state. However, in the extracellular bacterial alpha-lytic protease (alphaLP) these two processes have become decoupled. The native state of alphaLP is thermodynamically unstable, and when denatured, requires millennia (t(1/2), similar to 1,800 years)(1) to refold. Folding is made possible by an attached folding catalyst, the pro-region, which is degraded on completion of folding, leaving alphaLP trapped in its native state by a large kinetic unfolding barrier (t(1/2) similar to1.2 years)(1). alphaLP faces two very different folding landscapes: one in the presence of the pro-region controlling folding, and one in its absence restricting unfolding. Here we demonstrate that this separation of folding and unfolding pathways has removed constraints placed on the folding of thermodynamically stable proteins, and allowed the evolution of a native state having markedly reduced dynamic fluctuations. This, in turn, has led to a significant extension of the functional lifetime of alphaLP by the optimal suppression of proteolytic sensitivity.