Department of Medical Microbiology, University of Groningen and University Medical Center Groningen, Hanzeplein 1, P. O. Box 30001, 9700 RB Groningen, The Netherlands.
J Biol Chem. 2012 Aug 24;287(35):29789-800. doi: 10.1074/jbc.M112.378190. Epub 2012 Jul 5.
The twin-arginine translocation (Tat) pathway is dedicated to the transport of fully folded proteins across the cytoplasmic membranes of many bacteria and the chloroplast thylakoidal membrane. Accordingly, Tat-dependently translocated proteins are known to be delivered to the periplasm of Gram-negative bacteria, the growth medium of Gram-positive bacteria, and the thylakoid lumen. Here, we present the first example of a protein, YkuE of Bacillus subtilis, that is specifically targeted by the Tat pathway to the cell wall of a Gram-positive bacterium. The cell wall binding of YkuE is facilitated by electrostatic interactions. Interestingly, under particular conditions, YkuE can also be targeted to the cell wall in a Tat-independent manner. The biological function of YkuE was so far unknown. Our present studies show that YkuE is a metal-dependent phosphoesterase that preferentially binds manganese and zinc.
双精氨酸转运（Tat）途径专门用于将完全折叠的蛋白质穿过许多细菌的细胞质膜和叶绿体类囊体膜进行运输。相应地，已知 Tat 依赖性转运的蛋白质被递送到革兰氏阴性菌的周质、革兰氏阳性菌的生长培养基和类囊体腔中。在这里，我们提出了第一个例子，即枯草芽孢杆菌的 YkuE 蛋白，它是专门由 Tat 途径靶向革兰氏阳性菌细胞壁的。YkuE 的细胞壁结合是通过静电相互作用来促进的。有趣的是，在特定条件下，YkuE 也可以以 Tat 非依赖性的方式靶向细胞壁。YkuE 的生物学功能迄今未知。我们目前的研究表明，YkuE 是一种金属依赖性磷酸酯酶，它优先结合锰和锌。
