Untersuchungen zur Aktivierung der Zellulosebiosynthese in Salmonella Typhimurium durch zyklisches-di-GMP

纤维素是地球上最丰富的生物聚合物，因为它是植物生物量的关键成分。它是许多不同工业制造过程中使用的重要原料。虽然商业上几乎只使用植物来源的纤维素，但由于涉及大量基因，阐明植物中纤维素生物合成的基本过程是复杂的。本项目的重点是细菌有机体肠道沙门氏菌血清型鼠伤寒沙门氏菌的纤维素生产，它只含有一个纤维素生物合成操纵子，因此涉及的基因数量有限。由于小分子环二gmp与纤维素合酶的结合激活了纤维素的生物合成，本项目的实验旨在揭示其激活机制。生物合成蛋白的生化分析和位点特异性突变的结合将用于评估各种蛋白质结构域和基序对蛋白质特异性的重要性，以及可能涉及纤维素合酶及其相关蛋白质的空间定位的靶向过程。本项目的研究结果不仅对纤维素的生物合成有一定的影响，而且对其他受环二gmp调控的细菌胞外多糖系统也有一定的研究意义。

Cellulose is the most abundant biopolymer on earth, as it is the key component of plant biomass. It is an important raw material used in many different industrial manufacturing processes. Although commercially almost only plant derived cellulose is used, unraveling the basic processes of cellulose biosynthesis in plants is complex due to the high number of genes involved. This project focuses on cellulose production in the bacterial organism Salmonella enterica serovar Typhimurium which contains only one cellulose biosynthesis operon and therefore a limited number of genes involved. Since binding of the small molecule cyclic-di-GMP to the cellulose synthase activates cellulose biosynthesis, experiments of this project aim to unravel the mechanism of activation. A combination of biochemical analysis and site-specific mutations of biosynthesis proteins will be used to assess the importance of various protein domains and motifs for protein specificity and the targeting process which might involve spatial localization of the cellulose synthase and its associated proteins. The findings of this project will not only impact on cellulose biosynthesis but also on other bacterial exopolysaccharide systems regulated by cyclic-di-GMP.