糖類水解酵素之催化區含有兩個已知的重要催化殘基。我們假設這兩個重要催化殘基在結構排比中應該要被重疊在一起，並且希望觀察到相同功能分類下的糖類水解酵素，他們在催化殘基周圍有甚麼化學性質與幾何結構上的共同特徵。
蛋白質結構排比技術可以比較分析蛋白質結構間的同異處，並顯示蛋白質的共同特徵或獨特特徵。但是通過傳統的結構排比技術，催化殘基並不一定可以重疊在一起，所以我們設計一個座標點限制的結構排比，先將催化殘基的空間位置重疊，再進行剩餘殘基的排比。
最後，以EC3.2.1.4為實驗材料，其中包含反轉型和保留型兩種催化機制，多種折疊結構與SCOP結構區塊分類，觀察他們在不同階層分類下，分別有哪些殘基可以當作共同特徵。

For glycoside hydrolysis families, there are two known catalytic residues in the active site are important to the catalytic function. We assume the two catalytic residues should be superimposed together after alignment and we want to observe the chemical properties and geometric features around the two catalytic residues in same functional group.
Protein structure alignment can superimpose and comparison of variance components, the common or specific features of protein could be identified. But traditional structure alignment may not superimpose the catalytic residues in same coordinates, so we design a position constraint structure alignment that superimpose the catalytic residues first and align the remaining residues.
We select the 42 proteins in EC3.2.1.4 as experimental material. EC3.2.1.4 includes two mechanisms, inverting and retaining, 5 catalytic domain folds, many SCOP domains and glycoside hydrolysis families. Final, observe what residues can be the common features in the hierarchical classification.

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