Welinder K G
Eur J Biochem. 1985 Sep 16;151(3):497-504. doi: 10.1111/j.1432-1033.1985.tb09129.x.
The amino acid sequences of the 51% different horseradish peroxidase HRP C and turnip peroxidase TP 7 have previously been completed by us, but the three-dimensional structures are unknown. Recently the amino acid sequence and the crystal structure of yeast cytochrome c peroxidase have appeared. The three known apoperoxidases consist of 300 +/- 8 amino acid residues. The sequences have now been aligned and show 18% and 16% identity only, between the yeast peroxidase and plant peroxidase HRP C and TP 7, respectively. We show that different structural tests all support similar protein folds in plant peroxidases and yeast peroxidase and, therefore, a common evolutionary origin. The following tests support this thesis: (a) predicted helices in the plant peroxidases follow the complex pattern observed in the crystal structure of cytochrome c peroxidase; (b) their hydropathic profiles are similar and agree with observed buried and exposed peptide chain in cytochrome c peroxidase; (c) half-cystines which are distant in the amino acid sequence of plant peroxidases become spatial neighbours when fitted into the cytochrome c peroxidase model; (d) the two-domain structure proposed from limited proteolysis of apoperoxidase HRP C is observed in the crystal structure of cytochrome c peroxidase. The similarities and differences of the plant and yeast peroxidases and the reactive side chains of a plant peroxidase active site are described. The characteristics of Ca2+-binding sequences, derived from several superfamilies, are applied to predict the Ca2+-binding sequences in plant peroxidases.
我们此前已完成了51%不同的辣根过氧化物酶HRP C和芜菁过氧化物酶TP 7的氨基酸序列测定，但它们的三维结构尚不清楚。最近，酵母细胞色素c过氧化物酶的氨基酸序列和晶体结构已公布。三种已知的脱辅基过氧化物酶均由300±8个氨基酸残基组成。目前已对这些序列进行了比对，结果显示酵母过氧化物酶与植物过氧化物酶HRP C和TP 7之间的序列一致性分别仅为18%和16%。我们发现，不同的结构测试均支持植物过氧化物酶和酵母过氧化物酶具有相似的蛋白质折叠方式，因此它们有着共同的进化起源。以下测试支持这一论点：(a)植物过氧化物酶中预测的螺旋遵循细胞色素c过氧化物酶晶体结构中观察到的复杂模式；(b)它们的亲水性图谱相似，且与细胞色素c过氧化物酶中观察到的埋藏和暴露肽链一致；(c)当将植物过氧化物酶氨基酸序列中相距较远的半胱氨酸拟合到细胞色素c过氧化物酶模型中时，它们会成为空间上的相邻氨基酸；(d)脱辅基过氧化物酶HRP C经有限蛋白酶水解后提出的双结构域结构在细胞色素c过氧化物酶的晶体结构中也能观察到。本文描述了植物和酵母过氧化物酶的异同以及一种植物过氧化物酶活性位点的反应性侧链。从几个超家族推导得出的Ca2+结合序列的特征被用于预测植物过氧化物酶中的Ca2+结合序列。
