极端微生物中的柠檬酸合酶蛋白：基于结构模型的研究
Citrate synthase proteins in extremophilic organisms: Studies within a structure-based model
摘要：
我们研究了四个柠檬酸合酶同源二聚体蛋白在一个基于结构的粗粒度模型。这些蛋白质中有两种来自嗜热细菌，一种来自嗜冷细菌，一种来自嗜温生物;三种是封闭构象，两种是开放构象。即使这些蛋白质属于同一折叠，该模型也以与实验一致的方式区分了这些蛋白质的性质。例如，嗜热蛋白质是更稳定的crystalically比他们的嗜温和嗜冷的同源物，我们观察到的幅度的热波动附近的天然状态和热展开的动力学。稳定性水平与氨基酸接触的平均配位数和结构紧密度相关。在闭合构象中沿着序列的位置波动的模式不同于在开放构象中，包括在活性位点内。形成活性位点的氨基酸对的相关和非相关运动模式在开放和闭合构象中是非常不同的。两者合计，我们的研究结果表明，在天然结构中的氨基酸接触的精确位置似乎是一个关键因素，在解释的相似性和差异的热力学性质，当地的灵活性和集体运动的不同形式的酶。
英文摘要：
We study four citrate synthase homodimeric proteins within a structure-based coarse-grained model. Two of these proteins come from thermophilic bacteria, one from a cryophilic bacterium and one from a mesophilic organism; three are in the closed and two in the open conformations. Even though the proteins belong to the same fold, the model distinguishes the properties of these proteins in a way which is consistent with experiments. For instance, the thermophilic proteins are more stable thermodynamically than their mesophilic and cryophilic homologues, which we observe both in the magnitude of thermal fluctuations near the native state and in the kinetics of thermal unfolding. The level of stability correlates with the average coordination number for amino acids contacts and with the degree of structural compactness. The pattern of positional fluctuations along the sequence in the closed conformation is different than in the open conformation, including within the active site. The modes of correlated and anticorrelated movements of pairs of amino acids forming the active site are very different in the open and closed conformations. Taken together, our results show that the precise location of amino acid contacts in the native structure appears to be a critical element in explaining the similarities and differences in the thermodynamic properties, local flexibility and collective motions of the different forms of the enzyme.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
