8ILM

The cryo-EM structure of eight Rubisco large subunits (RbcL), two Arabidopsis thaliana Rubisco accumulation factors 1 (AtRaf1), and seven Arabidopsis thaliana Bundle Sheath Defective 2 (AtBSD2)

Summary for 8ILM

• Entry DOI: 10.2210/pdb8ilm/pdb
• EMDB information: 35536
• Descriptor: Ribulose bisphosphate carboxylase large chain, Protein BUNDLE SHEATH DEFECTIVE 2, chloroplastic, Rubisco accumulation factor 1.2, chloroplastic (3 entities in total)
• Functional Keywords: complex, biosynthetic protein, lyase-chaperone complex, lyase/chaperone
• Biological source: Synechococcus elongatus PCC 6301; More
• Total number of polymer chains: 19
• Total formula weight: 653551.36

Authors

Wang, R.,Song, H.,Zhang, W.,Wang, N.,Zhang, S.,Shao, R. (deposition date: 2023-03-03, release date: 2023-11-01, Last modification date: 2024-10-16)

Primary citation

Wang, R.,Song, H.,Zhang, W.,Wang, N.,Zhang, S.,Shao, R.,Liu, C.
Structural insights into the functions of Raf1 and Bsd2 in hexadecameric Rubisco assembly.
Mol Plant, 16:1927-1936, 2023

PubMed Abstract: Hexadecameric form I Rubisco, which consisting consists of eight large (RbcL) and eight small (RbcS) subunits, is the most abundant enzyme on earth. Extensive efforts to engineer an improved Rubisco to speed up its catalytic efficiency and ultimately increase agricultural productivity. However, difficulties with correct folding and assembly in foreign hosts or in vitro have hampered the genetic manipulation of hexadecameric Rubisco. In this study, we reconstituted Synechococcus sp. PCC6301 Rubisco in vitro using the chaperonin system and assembly factors from cyanobacteria and Arabidopsis thaliana (At). Rubisco holoenzyme was produced in the presence of cyanobacterial Rubisco accumulation factor 1 (Raf1) alone or both AtRaf1 and bundle-sheath defective-2 (AtBsd2) from Arabidopsis. RbcL released from GroEL is assembly capable in the presence of ATP, and AtBsd2 functions downstream of AtRaf1. Cryo-EM structures of RbcL-AtRaf1, RbcL-AtRaf1-AtBsd2, and RbcL revealed that the interactions between RbcL and AtRaf1 are looser than those between prokaryotic RbcL and Raf1, with AtRaf1 tilting 7° farther away from RbcL. AtBsd2 stabilizes the flexible regions of RbcL, including the N and C termini, the 60s loop, and loop 6. Using these data, combined with previous findings, we propose the possible biogenesis pathways of prokaryotic and eukaryotic Rubisco.

PubMed: 37853692
DOI: 10.1016/j.molp.2023.10.011

Experimental method

ELECTRON MICROSCOPY (3.3 Å)