The X-ray structure of a chitinase from the pathogenic fungus Coccidioides immitis
The X-ray structure of a chitinase from the pathogenic fungus Coccidioides immitis
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DOI：
10.1110/ps.9.3.544
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发表时间：
2000-03-01
期刊：
影响因子：
8
通讯作者：
Robertus, JD
中科院分区：
文献类型：
--
作者：
Hollis, T;Monzingo, AF;Robertus, JD
来自真菌病原体粗球孢子菌的几丁质酶的X射线结构已被解决到2.2埃分辨率。与18类水解酶家族的其他成员一样，这种427个残基的蛋白质是八链β/α桶。虽然缺乏N-末端几丁质锚定结构域，但该酶与粘质沙雷氏菌的几丁质酶非常相似。其中保守的功能是三个顺式肽键，都涉及保守的活性位点残基。活性位点由保守残基如色氨酸47、131、315、378、酪氨酸239和293以及精氨酸52和295形成。Glu171是水解机制中的催化酸;它被突变为Gln，活性被消除。Allosamidin是一种底物类似物，可强烈抑制18类酶。已观察到它与几丁质酶hevamine的结合，并且我们使用这两种酶的保守结构特征来预测与真菌酶结合的抑制剂。
The X-ray structure of chitinase from the fungal pathogen Coccidioides immitis has been solved to 2.2 Angstrom resolution. Like other members of the class 18 hydrolase family, this 427 residue protein is an eight-stranded beta/alpha-barrel. Although lacking an N-terminal chitin anchoring domain, the enzyme closely resembles the chitinase from Serratia marcescens. Among the conserved features are three cis peptide bonds, all involving conserved active site residues. The active site is formed from conserved residues such as tryptophans 47, 131, 315, 378, tyrosines 239 and 293, and arginines 52 and 295. Glu171 is the catalytic acid in the hydrolytic mechanism; it was mutated to a Gin, and activity was abolished. Allosamidin is a substrate analog that strongly inhibits the class 18 enzymes. Its binding to the chitinase hevamine has been observed, and we used conserved structural features of the two enzymes to predict the inhibitors binding to the fungal enzyme.