Siezen R J, Creemers J W, Van de Ven W J
Department of Biophysical Chemistry, NIZO, Ede, The Netherlands.
Eur J Biochem. 1994 Jun 1;222(2):255-66. doi: 10.1111/j.1432-1033.1994.tb18864.x.
A model is presented for the three-dimensional structure of the catalytic domain of the human serine proteinase furin and its interaction with model substrates. This homology model is based on the crystal structures of subtilisin BPN' and thermitase in complex with the inhibitor eglin, and it also applies to other members of the eukaryotic subtilisin-like proprotein convertases. Predictions are made of the general protein fold, inserted loops, disulfide bonds, Ca(2+)-binding sites and salt bridges. A detailed prediction of the substrate-binding region attempts to explain the basis of specificity for multiple basic residues preceding the cleavage site. Specific acidic residues in the S1, S2 and S4 subsites of the substrate-binding region of furin are identified which appear to be of particular importance, while residues of the S2', S3, S5 and S6 subsites may also contribute to substrate binding. Based on this model, protein engineering can be employed not only to test the predicted enzyme-substrate interactions, as demonstrated for human furin, but, equally importantly, to design proprotein convertases with a desired specificity, or to design novel substrates or inhibitors.
本文提出了一种关于人丝氨酸蛋白酶弗林蛋白酶催化结构域的三维结构及其与模型底物相互作用的模型。该同源模型基于枯草杆菌蛋白酶BPN'和嗜热菌蛋白酶与抑制剂依格尔丝氨酸蛋白酶抑制剂复合物的晶体结构，并且它也适用于真核枯草杆菌蛋白酶样前体蛋白转化酶的其他成员。对一般蛋白质折叠、插入环、二硫键、Ca(2+)结合位点和盐桥进行了预测。对底物结合区域的详细预测试图解释切割位点之前多个碱性残基特异性的基础。确定了弗林蛋白酶底物结合区域的S1、S2和S4亚位点中的特定酸性残基，这些残基似乎特别重要，而S2'、S3、S5和S6亚位点的残基也可能有助于底物结合。基于该模型，蛋白质工程不仅可用于测试预测的酶-底物相互作用，如对人弗林蛋白酶所证明的那样，而且同样重要的是，可用于设计具有所需特异性的前体蛋白转化酶，或设计新型底物或抑制剂。
