The role of protein acetylation in the regulation of photosynthetic light reactions.

蛋白质乙酰化在光合光反应调节中的作用。

• 批准号: 525030362
• 负责人: Professorin Dr. Iris Finkemeier
• 金额: --
• 依托单位: Arbeitsgruppe Plant Physiology
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/525030362?language=en
• 关键词: role; protein; acetylation; regulation; photosynthetic

The photosynthetic electron transport has to be dynamically regulated in dependence on environmental conditions to prevent photoinhibition and photodamage of the photosystems. Several chemical modifications of proteins are known to play important roles in modulating photosynthetic yield during plant acclimation responses. Next to phosphorylation, the acetylation of amino groups within proteins is a major posttranslational modification in all organisms and is particularly abundant on proteins involved in photosynthesis. N-terminal acetyltransferases or lysine acetyltransferases catalyze the transfer of the acetyl group from acetyl coenzyme A to the targeted amino group. In contrast to N-terminal acetylation, the acetylation of lysine residues (KAc) is reversible, whereby lysine deacetylases are responsible for the removal of acetyl groups from proteins. Recently, we identified eight new dual-specific acetyltransferases (GNTAs) in chloroplasts of Arabidopsis. The first characterization of GNAT2 revealed that this enzyme is indispensable for photosynthetic state transitions. In addition, the mutants show increased energy-dependent quenching at high light intensities compared to WT. While the first protein substrates of GNAT2 have been identified, the specific role of protein acetylation in the acclimation responses of the photosynthetic light reactions is still not understood on a mechanistic level. This project will provide novel biochemical insights into the functions of acetylation on selected target proteins, as well as the involvement of the closely related Arabidopsis plastidial acetyltransferases GNAT1-3 in regulating protein acetylation of photosynthetic proteins involved in energy-dependent quenching (see also Graphical Abstract P9). Latest in gel chemical crosslinking techniques will be used to study differences in thylakoid protein complex composition in dependence on light and genotype, which will be combined with electron cryotomography for 3D constructions. Specifically, we will focus on the role of acetylation in the photosynthetic acclimation responses to changes in light availability. This project will deliver on Aim 4 of GoPMF and contribute to GoPMF Aims 1, 2 and 3.

光合作用的电子传递必须根据环境条件进行动态调节，以防止光抑制和光系统的光损害。已知蛋白质的几种化学修饰在植物适应反应中调节光合作用的产量方面起着重要作用。仅次于磷酸化，蛋白质内氨基的乙酰化是所有生物体中主要的翻译后修饰，在参与光合作用的蛋白质中尤其丰富。N-末端乙酰基转移酶或赖氨酸乙酰基转移酶催化乙酰基从乙酰辅酶A转移到目标氨基。与N-末端乙酰化不同，赖氨酸残基的乙酰化(KAc)是可逆的，赖氨酸脱乙酰基酶负责从蛋白质中去除乙酰基。最近，我们在拟南芥的叶绿体中发现了8个新的双特异性乙酰转移酶(GNTA)。GNA2的首次表征表明，该酶是光合作用状态转换所必需的。此外，与WT相比，突变体在高光强下表现出更多的能量依赖猝灭。虽然GNA2的第一批蛋白质底物已被鉴定，但蛋白质乙酰化在光合光反应的适应反应中的具体作用在机制水平上仍不清楚。该项目将提供对选定目标蛋白的乙酰化功能的新的生化见解，以及密切相关的拟南芥胞质乙酰化转移酶GNA1-3参与调节与能量相关的猝灭所涉及的光合蛋白的蛋白质乙酰化(另见图形摘要P9)。最新的凝胶化学交联技术将被用来研究类囊体膜蛋白复合体组成随光和基因的差异，这将与电子冷冻断层扫描相结合进行3D构建。具体地说，我们将侧重于乙酰化在光合作用适应对光可获得性变化的反应中的作用。该项目将实现GoPMF的目标4，并有助于实现GoPMF的目标1、2和3。