Perani P, Zeggai S, Torriglia A, Courtois Y
Vieillissement et Pathologie de la Retine, INSERM, Unité U450 Developpement, 29, rue Wilhem, Paris, 75016, France.
Biochem Biophys Res Commun. 2000 Aug 11;274(3):841-4. doi: 10.1006/bbrc.2000.3191.
Leukocyte elastase inhibitor (LEI) is a cytosolic component of lung macrophages and blood leukocytes that inhibits neutrophil elastase. LEI is a member of the serpin superfamily, these proteins, mostly protease inhibitors, are thought to undergo a conformational change upon complex formation with proteinase that involves partial insertion of the hinge region of the reactive centre loop into a beta-sheet of the inhibitor. In this work three mutations were produced in the hinge region of elastase inhibitor that abolish the inhibition activity of LEI and transform the protein in a substrate of the elastase. This result demonstrates that the inhibitory mechanism of serpin is common to LEI.
白细胞弹性蛋白酶抑制剂（LEI）是肺巨噬细胞和血液白细胞的一种胞质成分，可抑制中性粒细胞弹性蛋白酶。LEI是丝氨酸蛋白酶抑制剂超家族的成员，这些蛋白质大多为蛋白酶抑制剂，被认为在与蛋白酶形成复合物时会发生构象变化，其中反应中心环的铰链区会部分插入抑制剂的β折叠中。在这项研究中，在弹性蛋白酶抑制剂的铰链区产生了三个突变，这些突变消除了LEI的抑制活性，并将该蛋白转化为弹性蛋白酶的底物。这一结果表明，丝氨酸蛋白酶抑制剂的抑制机制在LEI中是常见的。
