How do glycolytic routes and especially the newly discovered Entner-Doudoroff pathway contribute to the central carbon metabolism in cyanobacteria and do they play an essential role for carbon fixation and photosynthesis?

糖酵解途径，特别是新发现的 Entner-Doudoroff 途径如何促进蓝细菌的中心碳代谢？它们在碳固定和光合作用中发挥重要作用吗？

• 批准号: 367110946
• 负责人: Professorin Dr. Kirstin Gutekunst
• 金额: --
• 依托单位: Institut für Systembiotechnologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/367110946?language=en
• 关键词: How; do; glycolytic; routes; especially

We could recently show that both cyanobacteria and plants possess a previously overlooked third glycolytic route beside Emden-Meyerhof-Parnas (EMP) and oxidative pentose phosphate (OPP) pathway: the Entner-Doudoroff (ED) pathway (Chen et al. 2016, PNAS). Deletion of the ED pathway results in diminished growth both under mixotrophic (glucose and light) conditions and in a dark/light cycle (12h dark/12h light). Even though these observations indicate that the ED pathway is of physiological importance in cyanobacteria it does not quantify the share of this pathway. Therefore, flux analyses are absolutely essential to discover its true contribution to the central carbon metabolism in cyanobacteria. Interruption of both ED and OPP pathway results in a mutant with extremely poor growth under both mixotrophic and autotrophic conditions (unpublished). This result came as a surprise and clearly shows that glycolytic routes are essential under autotrophic conditions. The interplay between glycolytic routes, carbon fixation and photosynthesis could not be studied satisfactory in photoautotrophs until now, as one of the glycolytic routes was unknown. This proposal aims to quantify the fluxes through all glycolytic routes and the Calvin-Benson-Bassham (CBB) cycle of CO2 fixation under mixotrophic, heterotrophic and autotrophic conditions. Our main emphasis is to study the interconnection between glycolytic routes, carbon fixation and photosynthesis. We especially want to test the hypothesis, if glycolytic routes are essential to replenish the CBB cycle of CO2 fixation in the light and whether they are required to balance the photosynthetic electron transport. For this approach a combination of flux analyses, characterization of selected deletion mutants and physiological measurements are needed.

我们最近可以证明，蓝藻和植物除了emden - meyerhoff - parnas （EMP）和氧化戊糖磷酸（OPP）途径外，还具有以前被忽视的第三种糖酵解途径：enterner - doudoroff （ED）途径（Chen et al. 2016， PNAS）。在混合营养（葡萄糖和光照）条件下和暗/光循环（12h暗/12h光照）下，ED通路的缺失导致生长减少。尽管这些观察结果表明ED途径在蓝藻中具有生理重要性，但它并没有量化该途径的份额。因此，通量分析是绝对必要的，以发现其在蓝藻中央碳代谢的真正贡献。ED和OPP通路的中断导致突变体在混合营养和自养条件下生长极差（未发表）。这一结果令人惊讶，清楚地表明糖酵解途径在自养条件下是必不可少的。由于其中一条糖酵解途径尚不清楚，目前对光自养生物的糖酵解途径、固碳途径和光合作用之间的相互作用研究尚不满意。本研究旨在量化混合营养、异养和自养条件下所有糖酵解途径的通量和二氧化碳固定的Calvin-Benson-Bassham （CBB）循环。我们的主要重点是研究糖酵解途径，碳固定和光合作用之间的联系。我们特别想测试这个假设，如果糖酵解途径对于补充光下二氧化碳固定的CBB循环是必不可少的，以及它们是否需要平衡光合电子传递。对于这种方法，需要结合通量分析，选择缺失突变体的特征和生理测量。

项目成果

In-vivo quantification of electron flow through photosystem I - cyclic electron transport makes up about 35 % in a cyanobacterium.

• DOI: 10.1016/j.bbabio.2020.148353
• 发表时间: 2020-12
• 期刊: Biochimica et biophysica acta. Bioenergetics
• 作者: Marius Theune;S. Hildebrandt;A. Steffen-Heins;W. Bilger;Kirstin Gutekunst;Jens Appel

The structure and reactivity of the HoxEFU complex from the cyanobacterium Synechocystis sp. PCC 6803

• DOI: 10.1074/jbc.ra120.013136
• 发表时间: 2020-07-10
• 期刊: JOURNAL OF BIOLOGICAL CHEMISTRY
• 影响因子: 4.8
• 作者: Artz, Jacob H.;Tokmina-Lukaszewska, Monika;King, Paul W.
• 通讯作者: King, Paul W.