Genest Olivier, Seduk Farida, Ilbert Marianne, Méjean Vincent, Iobbi-Nivol Chantal
Laboratoire de Chimie Bactérienne, Institut de Biologie Structurale et Microbiologie, Centre National de la Recherche Scientifique Marseille, France.
Biochem Biophys Res Commun. 2006 Jan 20;339(3):991-5. doi: 10.1016/j.bbrc.2005.11.107.
TorD is the private chaperone of TorA, a periplasmic respiratory molybdoenzyme of Escherichia coli. In this study, it is demonstrated that TorD is required to maintain the integrity of the twin-arginine signal sequence of the cytoplasmic TorA precursors. In the absence of TorD, 35 out of the 39 amino acid residues of the signal peptide were lost and the proteolysis of the N-terminal extremity of TorA precursors was not prevented by the molybdenum cofactor insertion. We thus propose that one of the main roles of TorD is to protect the TorA signal peptide to allow translocation of the enzyme by the TAT system.
TorD是TorA的专属伴侣蛋白，TorA是大肠杆菌的一种周质呼吸钼酶。在本研究中，已证明TorD对于维持细胞质TorA前体的双精氨酸信号序列的完整性是必需的。在没有TorD的情况下，信号肽的39个氨基酸残基中有35个丢失，并且钼辅因子的插入并不能阻止TorA前体N末端的蛋白水解。因此，我们提出TorD的主要作用之一是保护TorA信号肽，以使该酶能够通过TAT系统进行转运。
