7E77

The structure of cytosolic TaPGI

7E77 の概要

• エントリーDOI: 10.2210/pdb7e77/pdb
• 分子名称: Glucose-6-phosphate isomerase (2 entities in total)
• 機能のキーワード: starch, biosynthetic protein, isomerase
• 由来する生物種: Triticum aestivum (Wheat)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 249315.69

構造登録者

Gao, F.,Liu, C.M. (登録日: 2021-02-25, 公開日: 2021-07-28, 最終更新日: 2023-11-29)

主引用文献

Gao, F.,Zhang, H.,Zhang, W.,Wang, N.,Zhang, S.,Chu, C.,Liu, C.
Engineering of the cytosolic form of phosphoglucose isomerase into chloroplasts improves plant photosynthesis and biomass.
New Phytol., 231:315-325, 2021

PubMed Abstract: Starch is the most abundant carbohydrate synthesized in plant chloroplast as the product of photosynthetic carbon assimilation, serving a crucial role in the carbon budget as storage energy. Phosphoglucose isomerase (PGI) catalyzes the interconversion between glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P), which are important metabolic molecules in starch synthesis within chloroplasts and sucrose synthesis in cytosol. Here, we found that the specific activity of recombinantly purified PGI localized in cytosolic PGI (PGIc) was much higher than its plastidic isoenzyme counterpart (PGIp) originated from wheat, rice and Arabidopsis, with wheat PGIc having by far the highest activity. Crystal structures of wheat TaPGIc and TaPGIp proteins were solved and the functional units were homodimers. The active sites of PGIc and PGIp, constituted by the same amino acids, formed different binding pockets. Moreover, PGIc showed slightly lower affinity to the substrate F6P but with much faster turnover rates. Engineering of TaPGIc into chloroplasts of a pgip mutant of Arabidopsis thaliana (atpgip) resulted in starch overaccumulation, increased CO assimilation, up to 19% more plant biomass and 27% seed yield productivity. These results show that manipulating starch metabolic pathways in chloroplasts can improve plant biomass and yield productivity.

PubMed: 33774822
DOI: 10.1111/nph.17368

実験手法

X-RAY DIFFRACTION (2.04 Å)