嗜热和嗜温6-磷酸葡萄糖酸脱氢酶的比较构象特性

Comparative conformational properties of thermophilic and mesophilic 6-phosphogluconate dehydrogenase.

作者信息

Veronese F M, Grandi C, Boccù E, Fontana A

出版信息

Experientia Suppl. 1976;26:147-55. doi: 10.1007/978-3-0348-7675-9_12.

Abstract

The structural properties of 6-phosphogluconate dehydrogenase from the mesophilic bacterium E. coli and the thermophilic B. stearothermophilus are compared using circular dichroism and fluorescence emission spectroscopy. The enzymes appear to possess a similar structure which does not change on heating up to the respective temperature of stability of the enzyme. The thermostability of the two 6-phosphogluconate dehydrogenases as determined by activity measurements parallels that determined by CD with the melting profile method, indicating that the loss of biological activity in the enzymes is directly related to the unfolding of the protein molecule. The pattern of unfolding of the proteins by the action of 8 M urea suggests that a core of enhanced conformational stability exists in the B. stearothermophilus enzyme.

摘要

利用圆二色性和荧光发射光谱法比较了嗜温细菌大肠杆菌和嗜热嗜热脂肪芽孢杆菌的6-磷酸葡萄糖酸脱氢酶的结构特性。这两种酶似乎具有相似的结构，在加热至各自酶的稳定温度时结构不变。通过活性测量确定的两种6-磷酸葡萄糖酸脱氢酶的热稳定性与用熔解曲线法通过圆二色性测定的热稳定性相似，表明酶中生物活性的丧失与蛋白质分子的解折叠直接相关。8M尿素作用下蛋白质的解折叠模式表明，嗜热脂肪芽孢杆菌酶中存在构象稳定性增强的核心。