Vitamin B6 metabolism in the Gram-positive model bacterium Bacillus subtilis

术语“维生素B6”统称为维生素吡哆醛（PL）、吡哆醇（PN）和吡哆胺（PM），以及相应的磷酸酯吡哆醛5 '-磷酸（PLP）、吡哆醇5'-磷酸（PNP）和吡哆胺5 '-磷酸（PMP）。PLP是最重要的B6维生素，因为它是许多蛋白质和酶的辅因子。在革兰氏阳性模式细菌枯草芽孢杆菌中，至少65种蛋白质需要PLP来发挥功能。B。枯草芽孢杆菌依赖于脱氧木酮糖-磷酸（DXP）非依赖性PdxST酶复合物用于PLP合成。其他生物通过DXP依赖性途径合成PLP，该途径涉及七种酶促反应。还观察到B.枯草杆菌能从环境中吸收B6维生素PL和PN产生PLP。然而，B6维生素的运输系统是未知的。在拟议的项目中，我们希望确定第一个细菌维生素B6转运蛋白。此外，我们的目标是阐明的作用，在PLP合成的辅酶PdxT和如何反应性B6维生素被转移到靶蛋白。最近，我们发现两个基因组的改变足以允许一个B。枯草杆菌菌株通过仅由两种非天然酶组成的截短的DXP依赖性途径产生PLP。遗传分析显示，未知功能的YtoQ蛋白参与维生素B6的生物合成。通过应用遗传和生物化学方法，我们的目标是阐明YtoQ蛋白的生理作用。此外，为了揭示新的维生素B6生物合成途径如何运作，我们将进行代谢组学分析。

The term "vitamin B6" collectively designates the vitamers pyridoxal (PL), pyridoxine (PN), and pyridoxamine (PM), and the respective phosphate esters pyridoxal 5’-phosphate (PLP), pyridoxine 5’-phosphate (PNP), and pyridoxamine 5’-phosphate (PMP). PLP is the most important B6 vitamer because it serves as a cofactor for many proteins and enzymes. In the Gram-positive model bacterium Bacillus subtilis at least 65 proteins require PLP for function. B. subtilis relies on the deoxyxylulose-phosphate (DXP)-independent PdxST enzyme complex for PLP synthesis. Other organisms synthesize PLP via the DXP-dependent pathway, which involves seven enzymatic reactions. It has also been observed that B. subtilis can take up the B6 vitamers PL and PN from the environment to produce PLP. However, the transport systems for the B6 vitamers are unknown. In the proposed project, we want to identify the first bacterial vitamin B6 transporter. Moreover, we aim to elucidate the role of the glutaminase PdxT in PLP synthesis and how the reactive B6 vitamer is transferred to the target proteins. Recently, we have found that two genomic alterations are sufficient to allow a B. subtilis strain to produce PLP via a truncated DXP-dependent pathway consisting of only two non-native enzymes. Genetic analyses revealed that the YtoQ protein of unknown function is involved in vitamin B6 biosynthesis. By applying genetic as well as biochemical approaches we aim to elucidate the physiological role of the YtoQ protein. Furthermore, to unravel how the novel vitamin B6 biosynthetic route operates, we will perform metabolome analyses.