9CI1

Anthoceros agrestis Rubisco octamer core complexed with Arabidopsis thaliana BSD2

9CI1 の概要

• エントリーDOI: 10.2210/pdb9ci1/pdb
• EMDBエントリー: 45605 45607
• 分子名称: Bundle Sheath Defective 2, Rubisco large subunit (2 entities in total)
• 機能のキーワード: anthoceros agrestis rubisco, photosynthesis
• 由来する生物種: Arabidopsis thaliana; 詳細
• タンパク質・核酸の鎖数: 16
• 化学式量合計: 539753.14

構造登録者

Ang, W.S.L.,Oh, Z.G.,Li, F.W.,Gunn, L.H. (登録日: 2024-07-02, 公開日: 2024-11-13, 最終更新日: 2024-12-11)

主引用文献

Oh, Z.G.,Robison, T.A.,Loh, D.H.,Ang, W.S.L.,Ng, J.Z.Y.,Li, F.W.,Gunn, L.H.
Unique biogenesis and kinetics of hornwort Rubiscos revealed by synthetic biology systems.
Mol Plant, 17:1833-1849, 2024

PubMed Abstract: Hornworts are the only land plants that employ a pyrenoid to optimize Rubisco's CO fixation, yet hornwort Rubisco remains poorly characterized. Here we assembled the hornwort Anthoceros agrestis Rubisco (AaRubisco) using the Arabidopsis thaliana SynBio expression system and observed the formation of stalled intermediates, prompting us to develop a new SynBio system with A. agrestis cognate chaperones. We successfully assembled AaRubisco and Rubisco from three other hornwort species. Unlike A. thaliana Rubisco, AaRubisco assembly is not dependent on RbcX or Raf2. Kinetic characterization reveals that hornwort Rubiscos exhibit a range of catalytic rates (3-10 s), but with similar affinity (∼30 μM) and specificity (∼70) for CO. These results suggest that hornwort Rubiscos do not comply with the long-held canonical catalytic trade-off observed in other land plants, providing experimental support that Rubisco kinetics may be phylogenetically constrained. Unexpectedly, we observed a 50% increase in AaRubisco catalytic rates when RbcX was removed from our SynBio system, without any reduction in specificity. Structural biology, biochemistry, and proteomic analysis suggest that subtle differences in Rubisco large-subunit interactions, when RbcX is absent during biogenesis, increases the accessibility of active sites and catalytic turnover rate. Collectively, this study uncovered a previously unknown Rubisco kinetic parameter space and provides a SynBio chassis to expand the survey of other Rubisco kinetics. Our discoveries will contribute to developing new approaches for engineering Rubisco with superior kinetics.

PubMed: 39491367
DOI: 10.1016/j.molp.2024.10.013

実験手法

ELECTRON MICROSCOPY (2.88 Å)