X-ray structure of the first 'extremo-α-carbonic anhydrase', a dimeric enzyme from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1
X-ray structure of the first 'extremo-α-carbonic anhydrase', a dimeric enzyme from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1
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DOI：
10.1107/s0907444913007208
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发表时间：
2013-06-01
影响因子：
2.2
通讯作者：
De Simone, Giuseppina
中科院分区：
文献类型：
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作者：
Di Fiore, Anna;Capasso, Clemente;De Simone, Giuseppina
SspCA是一种从嗜热细菌Sulphidium hydrogenibium yellow-stonense YO 3AOP 1中分离的新型“极端α-碳酸酐酶”，是一种有效的CO2水合催化剂，具有优异的热稳定性。事实上，SspCA甚至在加热到343-373 K几个小时后仍保持高催化活性。在这里，报道了这种α-碳酸酐酶（α-CA）的晶体结构，并阐明了其在高温下发挥功能的因素。特别是，该研究表明，增加的结构紧凑性，以及蛋白质表面上的带电残基的数量增加和更多的离子网络，似乎是参与这种酶的较高的热稳定性相对于其嗜温同系物的关键因素。这些发现非常重要，因为它们首次为理解α-CA家族中热稳定性的机制提供了结构基础。所获得的数据提供了一种工具，可用于工程化α-CA，以获得具有增强的热稳定性的酶，用于CO2捕获和封存过程的苛刻条件。
SspCA, a novel 'extremo-alpha-carbonic anhydrase' isolated from the thermophilic bacterium Sulfurihydrogenibium yellow-stonense YO3AOP1, is an efficient catalyst for the hydration of CO2 and presents exceptional thermostability. Indeed, SspCA retains a high catalytic activity even after being heated to 343-373 K for several hours. Here, the crystallographic structure of this alpha-carbonic anhydrase (alpha-CA) is reported and the factors responsible for its function at high temperature are elucidated. In particular, the study suggests that increased structural compactness, together with an increased number of charged residues on the protein surface and a greater number of ionic networks, seem to be the key factors involved in the higher thermostability of this enzyme with respect to its mesophilic homologues. These findings are of extreme importance, since they provide a structural basis for the understanding of the mechanisms responsible for thermal stability in the alpha-CA family for the first time. The data obtained offer a tool that can be exploited to engineer alpha-CAs in order to obtain enzymes with enhanced thermostability for use in the harsh conditions of the CO2 capture and sequestration processes.