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，因为它是植物生物质的关键组分。它是许多不同工业制造过程中使用的重要原材料。尽管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很复杂。该项目的重点是在细菌有机体沙门氏菌肠血清型鼠伤寒沙门氏菌中的纤维素生产，该细菌有机体仅包含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与纤维素合成酶的结合激活了纤维素的生物合成，因此本项目的实验旨在揭示激活机制。生物合成蛋白的生化分析和位点特异性突变的组合将用于评估各种蛋白质结构域和基序对蛋白质特异性和靶向过程的重要性，所述靶向过程可能涉及纤维素合酶及其相关蛋白的空间定位。该项目的研究结果不仅将影响纤维素生物合成，而且还将影响其他由cyclic-di-GMP调控的细菌胞外多糖系统。

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.