Auxiliary factors for chlorophyll biosynthesis and their potential contribution to the assembly of chlorophyll into chlorophyll-binding proteins

叶绿素的生物合成为光自养生物的光合作用提供必要的色素。虽然几乎所有的酶步骤都已被阐明，但该途径的时空组织及其与叶绿素组装成光合蛋白的功能耦合仍然是一个悬而未决的问题。这个子项目的目标是(I)深入阐明LIL3(捕光类蛋白3)和PITT同源的叶绿体定位的四肽重复蛋白(CpTPR)在组织叶绿素生物合成后期步骤中的功能和结构作用，以及(Ii)研究其他辅助因子的功能作用，这些辅助因子是叶绿素生物合成所必需的，或者是随后与叶绿素结合蛋白组装有关的链接，如OHP(单螺旋蛋白)、YCF54(假设的叶绿体开放阅读框架54)和CPL(POR1的查珀酮样蛋白(CPP1))。它们的相互作用伙伴旨在通过先进的生化方法，如蛋白质亲和层析和质谱学，或荧光和电子显微镜(部分与研究股的伙伴合作)，在野生型和突变植物中新确定或确认。因此，这些生理和生化分析有助于实现研究股的中心目标，即验证在类囊体膜中逐步组装具有光合作用活性的蛋白质复合体所需的组装因子。

Chlorophyll biosynthesis provides the essential pigments for photosynthesis in photoautotrophic organisms. While almost all enzymatic steps of have been elucidated, the spatio-temporal organization of the pathway as well as its functional coupling to the assembly of chlorophyll into photosynthetic proteins are still open questions. In continuation, the objective of this subproject is (i) the in-depth elucidation of the functional and structural roles of LIL3 (light-harvesting-like protein 3) and Pitt-homologous plastid-localized tetratricopeptide-repeat proteins (cpTPRs) for the organization of the late steps of chlorophyll biosynthesis and (ii) the examination of the functional roles of additional auxiliary factors which are required either for chlorophyll biosynthesis or the subsequent link to the assembly of chlorophyll-binding proteins, such as OHP (one-helix-protein), YCF54 (hypothetical chloroplast open reading frame 54) and CPL (Chaperone-like protein of POR1 (CPP1)-like protein). Their interaction partners are aimed to be newly identified or confirmed in wild-type and mutant plants by means of advanced biochemical methods, such as protein affinity chromatography and mass spectrometry, or fluorescence and electron microscopy (in part in cooperation with partners of the Research Unit). Thereby, these physiological and biochemical analyses contribute to the central objectives of the Research Unit to validate assembly factors required for the stepwise assembly of photosynthetically active protein complexes in thylakoid membranes.