Bilgin N, Lee J I, Zhu H Y, Dalbey R, von Heijne G
Department of Molecular Biology, Karolinska Institute Center for Biotechnology, NOVUM, Huddinge, Sweden.
EMBO J. 1990 Sep;9(9):2717-22. doi: 10.1002/j.1460-2075.1990.tb07458.x.
Leader peptidase (Lep) is a central component of the secretory machinery of Escherichia coli, where it serves to remove signal peptides from secretory proteins. It spans the inner membrane twice with a large C-terminal domain protruding into the periplasmic space. To investigate the importance of the different structural domains for the catalytic activity, we have studied the effects of a large panel of Lep mutants on the processing of signal peptides, both in vivo and in vitro. Our data suggest that the first transmembrane and cytoplasmic regions are not directly involved in catalysis, but that the second transmembrane region and the region immediately following it may be in contact with the signal peptide and/or located spatially close to the active site of Lep.
前导肽酶（Lep）是大肠杆菌分泌机制的核心组成部分，它负责从分泌蛋白中去除信号肽。它跨内膜两次，有一个大的C末端结构域突出到周质空间。为了研究不同结构域对催化活性的重要性，我们研究了大量Lep突变体在体内和体外对信号肽加工的影响。我们的数据表明，第一个跨膜区和细胞质区不直接参与催化，但第二个跨膜区及其紧邻区域可能与信号肽接触和/或在空间上靠近Lep的活性位点。
