Critical Roles of Transthylakoid Delta pH in the Energetics and Regulation of Photosynthesis

转囊体pH梯度（Δ pH）在光合作用中起着几个关键作用。 它驱动ATP的合成，通过减慢关键反应来控制光合电子转移，并触发保护反应中心免受光损伤的反馈调节系统。 此外，大的Δ pH值被认为使光系统II反应中心对光抑制敏感。 尽管有大量的研究，三角洲pH值和它影响的过程之间的定量关系是很差的定义。 拟议的工作旨在解决这些问题，通过开发非侵入性探针的管腔和基质pH值在体外和体内系统。 来自其他实验室以及我们实验室的初步工作已经证明，维多利亚水母绿色荧光蛋白（GFP）的突变体版本可以用作快速响应的细胞内pH探针，具有有用的pH敏感范围。 这些探针的表达将靶向烟草植物的基质和内腔区室，使我们能够非侵入性地探测这些区室的pH。 然后，我们将进行实验，使用原型荧光计，以评估这些探针的效用，在管腔和基质的pH值变化的调查。

The transthylakoid pH gradient (delta pH) plays several critical roles in photosynthesis. It drives the synthesis of ATP, controls photosynthetic electron transfer by slowing key reactions, and triggers feedback regulatory systems that protect reaction centers against photodamage. In addition, large delta pH values are thought to sensitize photosystem II reaction centers to photoinhibition. Despite a large number of studies, the quantitative relationships between delta pH and the processes it affects are poorly defined. The proposed work aims to address these issues by developing non-invasive probes of lumen and stromal pH to both in vitro and in vivo systems. Preliminary work from other laboratories, as well as ours, has demonstrated that mutant versions of the Aequorea victoria green fluorescent protein (GFP) can be used as rapidly responding intracellular pH probes, with a useful pH-sensitive ranges. Expression of these probes will be targeted to the stromal and lumenal compartments of tobacco plants, allowing us to non-invasively probe the pH of these compartments. We will then conduct experiments, using a prototype fluorimeter, to assess the utility of these probes to the investigation of pH changes in the lumen and stroma.