Structure of aminopepidase N from Escherichia coli suggests a compartmentalized, gated active site
Structure of aminopepidase N from Escherichia coli suggests a compartmentalized, gated active site
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DOI：
10.1073/pnas.0606167103
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发表时间：
2006-09-05
影响因子：
11.1
通讯作者：
Matthews, Brian W.
中科院分区：
文献类型：
--
作者：
Addlagatta, Anthony;Gay, Leslie;Matthews, Brian W.
大肠杆菌氨肽酶N是一种主要的金属蛋白酶，在蛋白水解途径中参与肽的受控水解。870-aa结构的测定表明，它有四个结构域类似于三角形相互作用因子F3。嗜热菌蛋白酶样活性位点被封闭在具有2，200埃体积的大空腔内（3），除了大约8-10埃的小开口之外，基底无法接近该大空腔。基于底物的抑制剂bestatin以最小的变化与蛋白质结合，表明这是酶的活性形式。先前描述的F3的结构具有三种不同的构象，被描述为“闭合”、“中间”和“开放”。and The aminopeptidase N.“然而，大肠杆菌比任何一种都封闭得多。总而言之，结果表明，这些参与细胞内肽降解的蛋白酶通过将活性位点封闭在大空腔内来防止不适当底物的无意水解。也有一些证据表明，酶的开放形式，它接受底物，保持无活性，直到它采取封闭形式。
Aminopeptidase N from Escherichia coli is a major metalloprotease that participates in the controlled hydrolysis of peptides in the proteolytic pathway. Determination of the 870-aa structure reveals that it has four domains similar to the tricorn-interacting factor F3. The thermolysin-like active site is enclosed within a large cavity with a volume of 2,200 angstrom(3), which is inaccessible to substrates except for a small opening of approximately 8-10 angstrom. The substrate-based inhibitor bestatin binds to the protein with minimal changes, suggesting that this is the active form of the enzyme. The previously described structure of F3 had three distinct conformations that were described as "closed," "intermediate," and "open." The structure of aminopeptidase N from E. coli, however, is substantially more closed than any of these. Taken together, the results suggest that these proteases, which are involved in intracellular peptide degradation, prevent inadvertent hydrolysis of inappropriate substrates by enclosing the active site within a large cavity. There is also some evidence that the open form of the enzyme, which admits substrates, remains inactive until it adopts the closed form.