Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-Ku, Nagoya 464-8602, Japan.
J Biol Chem. 2013 Jun 14;288(24):17451-9. doi: 10.1074/jbc.M112.433987. Epub 2013 May 2.
Elastase from Aspergillus sp. is an important factor for aspergillosis. AFUEI is an inhibitor of the elastase derived from Aspergillus fumigatus. AFUEI is a member of the I78 inhibitor family and has a high inhibitory activity against elastases of Aspergillus fumigatus and Aspergillus flavus, human neutrophil elastase and bovine chymotrypsin, but does not inhibit bovine trypsin. Here we report the crystal structure of AFUEI in two crystal forms. AFUEI is a wedge-shaped protein composed of an extended loop and a scaffold protein core. The structure of AFUEI shows remarkable similarity to serine protease inhibitors of the potato inhibitor I family, although they are classified into different inhibitor families. A structural comparison with the potato I family inhibitors suggests that the extended loop of AFUEI corresponds to the binding loop of the potato inhibitor I family, and AFUEI inhibits its cognate proteases through the same mechanism as the potato I family inhibitors.
从曲霉菌属中提取的弹性蛋白酶是曲霉菌病的一个重要因素。AFUEI 是烟曲霉衍生弹性蛋白酶的抑制剂。AFUEI 是 I78 抑制剂家族的一员，对烟曲霉和黄曲霉的弹性蛋白酶、人中性粒细胞弹性蛋白酶和牛胰凝乳蛋白酶具有高抑制活性，但不抑制牛胰蛋白酶。在这里，我们报告了 AFUEI 在两种晶体形式下的晶体结构。AFUEI 是一种由扩展环和支架蛋白核心组成的楔形蛋白。AFUEI 的结构与土豆抑制剂 I 家族的丝氨酸蛋白酶抑制剂表现出显著的相似性，尽管它们被归为不同的抑制剂家族。与土豆 I 家族抑制剂的结构比较表明，AFUEI 的扩展环对应于土豆抑制剂 I 家族的结合环，AFUEI 通过与土豆 I 家族抑制剂相同的机制抑制其同源蛋白酶。
