The folding landscape of Streptomyces griseus protease B reveals the energetic costs and benefits associated with evolving kinetic stability
The folding landscape of Streptomyces griseus protease B reveals the energetic costs and benefits associated with evolving kinetic stability
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灰色链霉菌蛋白酶 B 的折叠景观揭示了与不断变化的动力学稳定性相关的能量成本和收益
DOI：
10.1110/ps.03336804
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发表时间：
2004
期刊：
影响因子：
8
通讯作者：
D. Agard
中科院分区：
文献类型：
--
作者：
S. M. Truhlar;E. Cunningham;D. Agard
与大多数胞外细菌蛋白酶一样，灰色链霉菌蛋白酶B(SGPB)和α裂解酶(αLP)的合成是由它们折叠所必需的共价连接的前体区域组成的。在这篇文章中，我们描述了SGPB的折叠自由能景观，并将其与αLP和胰蛋白酶的折叠景观进行了比较，Trypsin是一种哺乳动物同源物，折叠独立于其酶原肽。与热力学稳定的胰酶天然状态相反，SGPB和αLP分别折叠到热力学边缘稳定或不稳定的天然状态。相反，它们表面上的稳定性是动态地产生的，因为它们展开了巨大的、高度合作的自由能垒。SGPB和αLP独特的去折叠转变延长了它们在高度降解条件下的功能寿命，超过了胰酶的功能寿命；然而，进化动力学稳定性的代价非常大，因为每增加2.4-8倍的蛋白酶抗性，就会伴随着自发折叠速率的∼10 5和热力学稳定性的∼5-9千卡/摩尔的成本。这些惩罚已经被日益有效的亲区域的共同进化所克服，以促进折叠。尽管有这些成本，动力学稳定性似乎是开发最大限度延长蛋白酶寿命的原生状态属性的有效机制。
Like most extracellular bacterial proteases, Streptomyces griseus protease B (SGPB) and α‐lytic protease (αLP) are synthesized with covalently attached pro regions necessary for their folding. In this article, we characterize the folding free energy landscape of SGPB and compare it to the folding landscapes of αLP and trypsin, a mammalian homolog that folds independently of its zymogen peptide. In contrast to the thermodynamically stable native state of trypsin, SGPB and αLP fold to native states that are thermodynamically marginally stable or unstable, respectively. Instead, their apparent stability arises kinetically, from unfolding free energy barriers that are both large and highly cooperative. The unique unfolding transitions of SGPB and αLP extend their functional lifetimes under highly degradatory conditions beyond that seen for trypsin; however, the penalty for evolving kinetic stability is remarkably large in that each factor of 2.4–8 in protease resistance is accompanied by a cost of ∼105 in the spontaneous folding rate and ∼5–9 kcal/mole in thermodynamic stability. These penalties have been overcome by the coevolution of increasingly effective pro regions to facilitate folding. Despite these costs, kinetic stability appears to be a potent mechanism for developing native‐state properties that maximize protease longevity.
影响因子：
2.9
作者：
Henkels, CH;Kurz, JC;Oas, TG
通讯作者：
Oas, TG
影响因子：
2.9
作者：
BRYAN, P;WANG, L;GALLAGHER, T
通讯作者：
GALLAGHER, T
影响因子：
6.8
作者：
Englander, SW;Sosnick, TR;Mayne, L
通讯作者：
Mayne, L