Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012, Bern, Switzerland.
Pflugers Arch. 2020 Sep;472(9):1129-1153. doi: 10.1007/s00424-020-02379-0. Epub 2020 May 6.
Glucose arguably is the most important energy carrier, carbon source for metabolites and building block for biopolymers in all kingdoms of life. The proper function of animal organs and tissues depends on the continuous supply of glucose from the bloodstream. Most animals can resorb only a small number of monosaccharides, mostly glucose, galactose and fructose, while all other sugars oligosaccharides and dietary fibers are degraded and metabolized by the microbiota of the lower intestine. Bacteria, in contrast, are omnivorous. They can import and metabolize structurally different sugars and, as a consortium of different species, utilize almost any sugar, sugar derivative and oligosaccharide occurring in nature. Bacteria have membrane transport systems for the uptake of sugars against steep concentration gradients energized by ATP, the proton motive force and the high energy glycolytic intermediate phosphoenolpyruvate (PEP). Different uptake mechanisms and the broad range of overlapping substrate specificities allow bacteria to quickly adapt to and colonize changing environments. Here, we review the structures and mechanisms of bacterial representatives of (i) ATP-dependent cassette (ABC) transporters, (ii) major facilitator (MFS) superfamily proton symporters, (iii) sodium solute symporters (SSS) and (iv) enzyme II integral membrane subunits of the bacterial PEP-dependent phosphotransferase system (PTS). We give a short overview on the distribution of transporter genes and their phylogenetic relationship in different bacterial species. Some sugar transporters are hijacked for import of bacteriophage DNA and antibacterial toxins (bacteriocins) and they facilitate the penetration of polar antibiotics. Finally, we describe how the expression and activity of certain sugar transporters are controlled in response to the availability of sugars and how the presence and uptake of sugars may affect pathogenicity and host-microbiota interactions.
葡萄糖可以说是所有生命形式中最重要的能量载体、代谢物的碳源和生物聚合物的构建块。动物器官和组织的正常功能依赖于血液中葡萄糖的持续供应。大多数动物只能吸收少量的单糖，主要是葡萄糖、半乳糖和果糖，而其他所有糖（包括低聚糖和膳食纤维）都在小肠微生物群的作用下被降解和代谢。相比之下，细菌是杂食动物。它们可以摄取和代谢结构不同的糖，并且作为不同物种的联合体，可以利用自然界中几乎任何存在的糖、糖衍生物和低聚糖。细菌具有针对糖的摄取的膜转运系统，这些摄取系统利用 ATP、质子动力和高能糖酵解中间产物磷酸烯醇丙酮酸（PEP）来驱动，以克服浓度梯度。不同的摄取机制和广泛重叠的底物特异性使细菌能够快速适应和殖民化不断变化的环境。在这里，我们回顾了细菌中（i）ATP 依赖性盒式（ABC）转运蛋白、（ii）主要易化剂（MFS）超家族质子转运蛋白、（iii）钠离子溶质转运蛋白（SSS）和（iv）细菌 PEP 依赖性磷酸转移酶系统（PTS）的酶 II 整合膜亚基的结构和机制。我们简要概述了转运基因在不同细菌物种中的分布及其系统发育关系。一些糖转运蛋白被劫持用于噬菌体 DNA 和抗菌毒素（细菌素）的输入，并促进极性抗生素的渗透。最后，我们描述了某些糖转运蛋白的表达和活性如何根据糖的可用性进行控制，以及糖的存在和摄取如何影响致病性和宿主微生物群相互作用。
