8ilb
The complexes of RbcL, AtRaf1 and AtBSD2 (LFB)
Structural highlights
FunctionRBL_SYNP6 RuBisCO catalyzes two reactions: the carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate in the photorespiration process. Both reactions occur simultaneously and in competition at the same active site.[HAMAP-Rule:MF_01338] Publication Abstract from PubMedHexadecameric form I Rubisco, consisting 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 to increase agricultural productivity have been undertaken. However, genetic manipulation of hexadecameric Rubisco has been hampered by its difficulty to fold and assemble correctly in foreign hosts or in vitro. Here we reconstituted Synechococcus sp. PCC6301 Rubisco with the chaperonin system and assembly factors from cyanobacteria and Arabidopsis thaliana (At) in vitro. Rubisco holoenzyme was produced in the presence of either Rubisco accumulation factor 1(Raf1) from cyanobacteria alone, or 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(8)-AtRaf1(8), RbcL(8)-AtRaf1(4)-AtBsd2(8), and RbcL(8) revealed that the interactions between RbcL-AtRaf1 are looser than those between prokaryotic RbcL-Raf1, with AtRaf1 tilting 7 degrees farther away from RbcL. AtBsd2 stabilizes the flexible regions of RbcL, including the N-, C-terminus, the 60s loop and loop 6. Using these data and combined with previous findings, we propose models for the biogenesis pathways of prokaryotic and eukaryotic Rubisco. Structural insight into the functions of Raf1 and Bsd2 in hexadecameric Rubisco assembly.,Wang R, Song H, Zhang W, Wang N, Zhang S, Shao R, Liu C Mol Plant. 2023 Oct 17:S1674-2052(23)00325-8. doi: 10.1016/j.molp.2023.10.011. PMID:37853692[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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