Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts

Abstract

The chloroplast ATP synthase produces the ATP needed for photosynthesis and plant growth. The trans-membrane flow of protons through the ATP synthase rotates an oligomeric assembly of c subunits, the c-ring. The ion-to-ATP ratio in rotary F1Fo-ATP synthases is defined by the number of c-subunits in the rotor c-ring. Engineering the c-ring stoichiometry is therefore a possible route to manipulate ATP synthesis by the ATP synthase and hence photosynthetic efficiency in plants. Here we describe the construction of a tobacco (Nicotiana tabacum) chloroplast atpH (chloroplastic ATP synthase subunit c gene) mutant in which the c-ring stoichiometry was increased from 14 to 15 c-subunits. Although the abundance of the ATP synthase was decreased to 25% of wild-type (WT) levels, the mutant lines grew as well as WT plants and photosynthetic electron transport remained unaffected. To synthesise the necessary ATP for growth, we found that the contribution of the membrane potential to the proton motive force was enhanced to ensure a higher proton flux via the c15-ring without unwanted low pH-induced feedback inhibition of electron transport. Our work opens avenues to manipulate plant ion-to-ATP ratios with potentially beneficial consequences for photosythesis.

Assessing the Impacts of Cu and Mo Engineered Nanomaterials on Crop Plant Growth Using a Targeted Proteomics Approach

“…In addition, the presence of proteins related to the photorespiratory pathway (e.g., peroxisomal aminotransferases and photosystem II stability/assembly factor HCF136) in cluster #1 further emphasizes the active engagement of leaves in these processes. Moreover, since mitochondrial electron transport and ATP synthesis play a crucial role in synthesizing ATP, which supports the energetic demands of photosynthetic tissues and plant growth, 39 it is logical to find the related proteins in high concentrations in leaves (e.g., ATP synthase beta subunit and ATP synthase delta chain). However, ATP synthase F1-ATPase (cluster #3) and transport p- and v-ATPase (cluster #4), which are also involved in ATP synthesis pathway, showed high concentration in stems other than leaves.…”

Editorial: Functions, working mechanisms, and regulation of rotary ATPases and Ductin proteins

“…The improved structure models combined with kinetic single-molecule spectroscopic and other novel biophysical studies (e.g., Otomo et al, 2022 ; Kobayashi et al, 2023 ; Pérez et al, 2023 ) and molecular simulations (e.g., Blanc and Hummer, 2024 ) will lead to more detailed theoretical description of the catalysis-transport mechanism of F-, V- and A-type rotary enzymes. Regarding biological function, research is strong on the assembly and the activity of the rotary enzymes (and some of their subunits, e.g., c -ring proteins) in general, but also in certain membrane fusion and pore formation processes ( Novitskaia et al, 2019 ; Banerjee and Kane, 2020 ; Mnatsakanyan and Jonas, 2020 ; Abuammar et al, 2021 ; Lapashina et al, 2022 ; Nesci, 2022 ; Wilkens et al, 2023 ; Yamamoto et al, 2023 ). Therefore, new insights will likely emerge on the biological regulation of the reversible assembly and activity of rotary enzymes in the near future.…”

High-throughput algorithm predicts F-Type ATP synthase rotor ring stoichiometries of 8 to 27 protomers

“…Apparently, c-ring stoichiometry is defined by the amino acids placed at the interfaces between adjacent c subunits, and usage of mutations to alter stoichiometry was previously demonstrated: natural c 11 -ring from Ilyobacter tartaricus was transformed into c <11 , c 12 , c 13 , c 14 , and c >14 rings (Pogoryelov et al 2012); c 13 -ring from Bacillus pseudofirmus OF4 was transformed into c 12 rings (Preiss et al . 2013); and c 14 ring from chloroplasts of a plant Nicotiana tabacum was transformed into c 15 ring (Yamamoto et al . 2023).…”

“…2023). Engineered c-rings could be used for modulating organism properties, as demonstrated for example in Yamamoto et al . 2023.…”