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

植物中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主要同化途径的调节网络的一部分。半胱氨酸合酶的蛋白质复合物存在于三个细胞隔室中，并且被认为通过可逆的蛋白质-蛋白质相互作用作为初级硫代谢的调节剂。该项目的目的是有针对性地放松特定隔室中半胱氨酸合酶复合物的形成，以研究这种操纵在植物中的后果。这将在三个阶段中实现：“计算机模拟”阶段将包括半胱氨酸合酶复合物的两个亚基的现有结构数据的详细分析和干扰亚基相互作用的多肽候选物的设计。在“体外”阶段，设计的肽的功能性将通过生物物理和生物化学方法使用重组纯化形式的亚基来验证。“体内”阶段将包括用预先选择的构建体转化烟草和鉴定线粒体和叶绿体中半胱氨酸合成失调的基因型。这将使我们能够追踪半胱氨酸合酶复合物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.