He Bixi, Sachla Ankita J, Helmann John D
Department of Microbiology, Cornell University, 370 Wing Hall, 123 Wing Drive, Ithaca, New York 14853-8101, USA.
bioRxiv. 2023 Apr 10:2023.04.10.536223. doi: 10.1101/2023.04.10.536223.
Cytosolic metalloenzymes acquire metals from buffered intracellular pools. How exported metalloenzymes are appropriately metalated is less clear. We provide evidence that TerC family proteins function in metalation of enzymes during export through the general secretion (Sec-dependent) pathway. strains lacking MeeF(YceF) and MeeY(YkoY) have a reduced capacity for protein export and a greatly reduced level of manganese (Mn) in the secreted proteome. MeeF and MeeY copurify with proteins of the general secretory pathway, and in their absence the FtsH membrane protease is essential for viability. MeeF and MeeY are also required for efficient function of the Mn -dependent lipoteichoic acid synthase (LtaS), a membrane-localized enzyme with an extracytoplasmic active site. Thus, MeeF and MeeY, representative of the widely conserved TerC family of membrane transporters, function in the co-translocational metalation of Mn -dependent membrane and extracellular enzymes.
胞质金属酶从缓冲的细胞内池中获取金属。而输出的金属酶如何进行适当的金属化则不太清楚。我们提供的证据表明，TerC家族蛋白在通过一般分泌（Sec依赖性）途径输出过程中，在酶的金属化过程中发挥作用。缺乏MeeF（YceF）和MeeY（YkoY）的菌株蛋白质输出能力降低，分泌蛋白质组中的锰（Mn）水平大大降低。MeeF和MeeY与一般分泌途径的蛋白质共纯化，在它们缺失的情况下，FtsH膜蛋白酶对生存能力至关重要。Mn依赖性脂磷壁酸合酶（LtaS）是一种具有胞外活性位点的膜定位酶，其有效功能也需要MeeF和MeeY。因此，作为广泛保守的膜转运蛋白TerC家族的代表，MeeF和MeeY在Mn依赖性膜酶和细胞外酶的共转运金属化中发挥作用。
