Structures and mechanisms of enzymes involved in bacterial chlorophyll biosynthesis

叶绿素和细菌叶绿素对捕获全球能源需求至关重要。在细菌和植物中，这些色素分子是光合作用装置的重要组成部分，光合作用装置负责将光转化为化学能。我们的工作重点是对以下（细菌）叶绿素生物合成酶的分子理解：3-乙烯基细菌叶绿素内酯a水合酶（BchF）和3-羟乙基细菌叶绿素内酯a脱氢酶（BchC）催化细菌叶绿素a合成的倒数第二步。o2依赖性或非o2依赖性Mg原卟啉IX单甲基酯环化酶是合成所有叶绿素中存在的五环系统所必需的。所有必需环化酶蛋白亚基的鉴定和表征是本项目的中心目标。光依赖性原叶绿内酯氧化还原酶（LPOR）进行严格的光依赖性催化。期望携带多种辅助因子的酶（如辅酶B12、s -腺苷蛋氨酸或二铁中心）采用新的催化原理。晶体结构测定结合生物化学和生物物理分析将揭示（细菌）叶绿素生物合成后期步骤的原子性理解。

Chlorophylls and bacteriochlorophylls are essential for the capturing of the global energy demand. In bacteria and plants, these pigment molecules are essential parts of the photosynthetic apparatus which is responsible for the conversion of light into chemical energy. Our work is focused on the molecular understanding of the following (bacterio)chlorophyll biosynthetic enzymes: 3-vinyl bacteriochlorophyllide a hydratase (BchF) and 3-hydroxyethyl bacteriochlorophyllide a dehydrogenase (BchC) catalyze the penultimate steps of bacteriochlorophyll a synthesis. O2-dependent or O2-independent Mg protoporphyrin IX monomethylester cyclase is essential for the synthesis of the fifth ring system found in all chlorophylls. The identification and characterization of all essential cyclase protein subunits is a central goal of this project. Light-dependent protochlorophyllide oxidoreductase (LPOR) performs a strictly light-dependent catalysis. Novel catalytic principles employed by enzymes carrying multiple cofactors (e.g. coenzyme B12, S-adenosyl methionine or diiron centers) are expected. Crystal structure determination in combination with biochemical and biophysical analyses will reveal the atomistic understanding of the late steps of (bacterio)chlorophyll biosynthesis.