Structures of the psychrophilic Alteromonas haloplanctis α-amylase give insights into cold adaptation at a molecular level
Structures of the psychrophilic Alteromonas haloplanctis α-amylase give insights into cold adaptation at a molecular level
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DOI：
10.1016/s0969-2126(98)00149-x
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发表时间：
1998-12-15
期刊：
影响因子：
5.7
通讯作者：
Haser, R
中科院分区：
文献类型：
--
作者：
Aghajari, N;Feller, G;Haser, R
背景：来自嗜冷（冷适应）微生物的酶在接近 0 摄氏度的温度下工作，其中嗜温和嗜热对应物的活性急剧降低。人们普遍认为嗜热与刚性蛋白质有关，而嗜冷酶则倾向于更加灵活。结果：根据嗜冷蛋白质的分子结构，深入了解蛋白质的冷适应能力。为此，我们以 2.4 埃的分辨率确定了来自盐生交替单胞菌的嗜冷 α-淀粉酶的重组形式的结构。我们将其与最近以 2.0 埃分辨率解析的野生型酶的结构以及其嗜温对应物的可用结构进行了比较。这些比较研究使我们能够确定冷适应的可能决定因素。结论：我们提出，分子表面弹性的增加和刚性较低的蛋白质核心以及域间相互作用的减少，是构象灵活性的决定因素，从而允许在寒冷环境中有效的酶催化。
Background: Enzymes from psychrophilic (cold-adapted) microorganisms operate at temperatures close to 0 degrees C, where the activity of their mesophilic and thermophilic counterparts is drastically reduced. It has generally been assumed that thermophily is associated with rigid proteins, whereas psychrophilic enzymes have a tendency to be more flexible.Results: Insights into the cold adaptation of proteins are gained on the basis of a psychrophilic protein's molecular structure. To this' end, we have determined the structure of the recombinant form of a psychrophilic a-amylase from Alteromonas haloplanctis at 2.4 Angstrom resolution. We have compared this with the structure of the wild-type enzyme, recently solved at 2.0 Angstrom resolution, and with available structures of their mesophilic counterparts. These comparative studies have enabled us to identify possible determinants of cold adaptation.Conclusions: We propose that an increased resilience of the molecular surface and a less rigid protein core, with less interdomain interactions, are determining factors of the conformational flexibility that allows efficient enzyme catalysis in cold environments.