2pen

Structural highlights

Function

RBCX_SYNP2 An RbcL-specific chaperone. Required for assembly of the RbcL8 core, acting downstream of the major chaperonin (GroEL-GroES). Acts on newly folded RbcL, has a transient dynamic interaction with RbcL and is eventually displaced by RbcS (PubMed:17574029). The central cleft of the RbcX homodimer (RbcX2) binds the C-terminus of an RbcL monomer, stabilizing the C-terminus and probably preventing its reassociation with chaperonin GroEL-ES. At the same time the peripheral region of RbcX2 binds a second RbcL monomer, bridging the RbcL homodimers in the correct orientation. The RbcX2(2)-bound RbcL dimers then assemble into the RbcL8 core (RbcL8-(RbcX2)8). RbcS binding triggers the release of RbcX2 (By similarity). Required for optimal reconstitution of RuBisCO into its RbcL8S8 holoenzyme form upon expression of rbcL-rbcS subunits in E.coli, and probably also in situ. A frameshift mutation that replaces half the protein reduces accumulation of both RbcL and RbcS subunits and halves activity of RuBisCO in situ and in E.coli (PubMed:15564522).[UniProtKB:Q44212]^{[1] [2]}

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

References

1. ↑ Onizuka T, Endo S, Akiyama H, Kanai S, Hirano M, Yokota A, Tanaka S, Miyasaka H. The rbcX gene product promotes the production and assembly of ribulose-1,5-bisphosphate carboxylase/oxygenase of Synechococcus sp. PCC7002 in Escherichia coli. Plant Cell Physiol. 2004 Oct;45(10):1390-5. doi: 10.1093/pcp/pch160. PMID:15564522 doi:http://dx.doi.org/10.1093/pcp/pch160
2. ↑ Saschenbrecker S, Bracher A, Rao KV, Rao BV, Hartl FU, Hayer-Hartl M. Structure and function of RbcX, an assembly chaperone for hexadecameric Rubisco. Cell. 2007 Jun 15;129(6):1189-200. PMID:17574029 doi:10.1016/j.cell.2007.04.025