Why an increase in activity of an enzyme in the Calvin–Benson cycle does not always lead to an increased photosynthetic CO2 uptake rate?—a theoretical analysis
Why an increase in activity of an enzyme in the Calvin–Benson cycle does not always lead to an increased photosynthetic CO2 uptake rate?—a theoretical analysis
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为什么卡尔文-本森循环中酶活性的增加并不总是导致光合二氧化碳吸收率的增加？理论分析
DOI：
10.1093/insilicoplants/diaa009
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发表时间：
2020-12
期刊：
影响因子：
3.1
通讯作者：
Xin-Guang Zhu
中科院分区：
文献类型：
--
作者：
Honglong Zhao;Qiming Tang;Tiangen Chang;Yi Xiao;Xin-Guang Zhu
Abstract. Overexpressing Calvin–Benson cycle (CBC) enzyme shown to limit the flow of CO2 through the cycle is a major approach to improve photosynthesis. Though control coefficients of CBC enzymes vary under different environmental and developmental conditions, it is usually implicitly assumed that enzymes in the CBC have a monotonic impact on the CBC fluxes. Here, with a dynamic systems model of the photosynthetic carbon metabolism, we show that, for glycerate-3-phosphate kinase (PGAK), fructose-1,6-bisphosphatase (FBPase), fructose-1,6-bisphosphate aldolase (FBA) and transketolase (TKa), individually increasing activity of these CBC enzymes theoretically leads to an initial increase then decrease in the fluxes through the CBC. Also, the inhibition constants of adenosine diphosphate (ADP) for PGAK and of fructose-6-phosphate (F6P) for FBPase influence the CBC flux in a biphasic manner. These predicted enzymes showing a biphasic manner are always located in different subcycles of the CBC, which consume the shared substrates in the early steps in the CBC and produce intermediates used as substrates for enzymes in the later reactions. We show that the excessive increase in activities of enzymes in one subcycle consuming the shared metabolite could cause low concentrations of metabolites in the other subcycles, which results in low reaction rates of the later reactions and hence lowers overall CBC flux. This study provides a model to explain the underlying reasons that overexpression of enzymes in the CBC sometimes can negatively impact photosynthesis. We find that balanced activities of enzymes in the subcycles of the CBC are required to gain a higher efficiency of the CBC.
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表达源自蓝藻的 Ictb 和 FBP/Sbpase 的转基因水稻表现出增强的光合作用和叶肉对 CO2 的传导性
影响因子：
3.7
作者：
Gong HY;Li Y;Fang G;Hu DH;Jin WB;Wang ZH;Li YS
通讯作者：
Li YS
影响因子：
4.6
作者：
Ding F;Wang M;Zhang S;Ai X
通讯作者：
Ai X
影响因子：
6.9
作者：
Köhler IH;Ruiz-Vera UM;VanLoocke A;Thomey ML;Clemente T;Long SP;Ort DR;Bernacchi CJ
通讯作者：
Bernacchi CJ
SBPase活性增加可改善温室条件下生长的小麦的光合作用和谷物产量。
DOI：
10.1098/rstb.2016.0384
发表时间：
2017-09-26
期刊：
Philosophical transactions of the Royal Society of London. Series B, Biological sciences
影响因子：
--
作者：
Driever SM;Simkin AJ;Alotaibi S;Fisk SJ;Madgwick PJ;Sparks CA;Jones HD;Lawson T;Parry MAJ;Raines CA
通讯作者：
Raines CA
影响因子：
7.2
作者：
KOSSMANN, J;SONNEWALD, U;WILLMITZER, L
通讯作者：
WILLMITZER, L