Molecular approaches towards control of sulfur flux in plants through selective deregulation of cysteine synthase complexes

植物中的硫同化和半胱氨酸生物合成是控制植物适应性和作物生产的初级同化途径调控网络的一部分。半胱氨酸合酶的蛋白质复合物存在于三个细胞区室中，被认为是通过可逆的蛋白质-蛋白质相互作用调节初级硫代谢。该项目的目的是有针对性地解除对特定隔室中半胱氨酸合成酶复合物形成的管制，以研究这种操作在植物中的后果。这将分三个阶段实现：“在硅”阶段将包括对半胱氨酸合成酶复合物的两个亚基的现有结构数据的详细分析，以及干扰亚基相互作用的多肽候选物的设计。在“体外”阶段，设计的肽的功能将通过使用亚基的重组纯化形式的生物物理和生化方法进行验证。“体内”阶段将包括用预先选择的构建体转化烟草，以及鉴定线粒体和叶绿体中半胱氨酸合成不受管制的基因型。这将使我们能够追踪半胱氨酸合酶复合体内调节的结构基础及其在硫通量调节中的作用。

Sulfur assimilation and cysteine biosynthesis in plants are part of the regulatory network of primary assimilation pathways that govern plant fitness and crop production. Protein complexes of cysteine synthase exist in three cellular compartments and are believed to act as regulators of primary sulfur metabolism via reversible protein-protein interaction. The aim of the project is a targeted deregulation of the formation of cysteine synthase complexes in specific compartments to study the consequences of such manipulations in planta. This will be achieved in three stages: An 'in silico' stage will include detailed analyses of the existing structural data of the two subunits of the cysteine synthase complex and the design of polypeptide candidates interfering with the interaction of subunits. During an 'in vitro' stage, the functionality of the designed peptides will be verified by biophysical and biochemical methods using recombinant purified forms of the subunits. The 'in vivo' stage will include transformation of tobacco with the pre-selected constructs and identification of genotypes with deregulated cysteine synthesis in mitochondria and chloroplasts. This will enable us to track down the structural basis of regulation within the cysteine synthase complex and its role in regulation of sulfur flux.