Sparrow-Muñoz Ignacio, Chen Timothy C, Burgess Steven J
Department of Plant Biology, University of Illinois Urbana-Champaign, Champaign, IL, U.S.A.
Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Champaign, IL, U.S.A.
Biochem Soc Trans. 2023 Apr 26;51(2):627-637. doi: 10.1042/BST20221281.
Rubisco activase (RCA) catalyzes the release of inhibitory sugar phosphates from ribulose-1,6-biphosphate carboxylase/oxygenase (Rubisco) and can play an important role in biochemical limitations of photosynthesis under dynamic light and elevated temperatures. There is interest in increasing RCA activity to improve crop productivity, but a lack of understanding about the regulation of photosynthesis complicates engineering strategies. In this review, we discuss work relevant to improving RCA with a focus on advances in understanding the structural cause of RCA instability under heat stress and the regulatory interactions between RCA and components of photosynthesis. This reveals substantial variation in RCA thermostability that can be influenced by single amino acid substitutions, and that engineered variants can perform better in vitro and in vivo under heat stress. In addition, there are indications RCA activity is controlled by transcriptional, post-transcriptional, post-translational, and spatial regulation, which may be important for balancing between carbon fixation and light capture. Finally, we provide an overview of findings from recent field experiments and consider the requirements for commercial validation as part of efforts to increase crop yields in the face of global climate change.
核酮糖-1,5-二磷酸羧化酶/加氧酶活化酶（RCA）催化从1,5-二磷酸核酮糖羧化酶/加氧酶（Rubisco）释放抑制性糖磷酸，并且在动态光照和高温下光合作用的生化限制中可能发挥重要作用。人们对提高RCA活性以提高作物生产力很感兴趣，但对光合作用调控的缺乏了解使工程策略变得复杂。在这篇综述中，我们讨论了与提高RCA相关的工作，重点是在理解热胁迫下RCA不稳定的结构原因以及RCA与光合作用组件之间的调控相互作用方面取得的进展。这揭示了RCA热稳定性的显著差异，这种差异可受单个氨基酸取代的影响，并且工程变体在热胁迫下在体外和体内的表现可能更好。此外，有迹象表明RCA活性受转录、转录后、翻译后和空间调控，这对于平衡碳固定和光捕获可能很重要。最后，我们概述了近期田间试验的结果，并考虑了作为应对全球气候变化增加作物产量努力一部分的商业验证要求。
