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From Proteopedia
Crystal structure of RuBisCO accumulation factor Raf1 from Anabaena sp. PCC 7120
Structural highlights
FunctionRAF1_NOSS1 A major RuBisCO chaperone. Acts after GroEL-GroES chaperonin to fold and/or assemble the large subunit of RuBisCO (ccbL, rbcL). Cooperates with RbcX in RbcL folding, plays the major role in assembly of dimers into RbcL(8)-Raf1(8) intermediate complexes. RbcS replaces Raf1, leading to holoenzyme formation.[HAMAP-Rule:MF_00856][1] In vitro acts as an antagonist to CcmM35, suggesting it might regulate RuBisCO condensation and decondensation.[2] Publication Abstract from PubMedThe folding and assembly of RuBisCO, the most abundant enzyme in nature, needs a series of chaperones, including the RuBisCO accumulation factor Raf1, which is highly conserved in cyanobacteria and plants. Here, we report the crystal structures of Raf1 from cyanobacteria Anabaena sp. PCC 7120 and its complex with RuBisCO large subunit RbcL. Structural analyses and biochemical assays reveal that each Raf1 dimer captures an RbcL dimer, with the C-terminal tail inserting into the catalytic pocket, and further mediates the assembly of RbcL dimers to form the octameric core of RuBisCO. Furthermore, the cryo-electron microscopy structures of the RbcL-Raf1-RbcS assembly intermediates enable us to see a dynamic assembly process from RbcL8Raf18 to the holoenzyme RbcL8RbcS8. In vitro assays also indicate that Raf1 can attenuate and reverse CcmM-mediated cyanobacterial RuBisCO condensation. Combined with previous findings, we propose a putative model for the assembly of cyanobacterial RuBisCO coordinated by the chaperone Raf1. Molecular basis for the assembly of RuBisCO assisted by the chaperone Raf1.,Xia LY, Jiang YL, Kong WW, Sun H, Li WF, Chen Y, Zhou CZ Nat Plants. 2020 May 25. pii: 10.1038/s41477-020-0665-8. doi:, 10.1038/s41477-020-0665-8. PMID:32451445[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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