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. Required for optimal reconstitution of RbcL(8) upon expression in E.coli (PubMed:28108864). Has been suggested to be involved in RuBisCO recycling and homeostasis rather than assembly (Probable). Homodimer. Forms an RbcL(8)-Raf1(8) complex. Forms complexes of many stoichiometries with RbcL with and without RbcS. RbcX and Raf1 can bind simultaneously to RbcL (By similarity). Interacts with both RuBisCO subunits (ccbL, ccbS), GroEL, DnaK and alpha and beta phycocyanin (cpcA, cpcB) in pull-down experiments with tagged protein. C-terminally tagged Raf1 does not interact with either RuBisCO subunit, suggesting its C-terminus is involved in binding (PubMed:28108864). Has 3 domains, the N-terminal alpha-helical domain, an extended flexible linker and the C-terminal beta-sheet domain. The 2 C-terminal beta-sheet domains are swapped and pack against each other to form the dimer interface. No visible phenotype under normal growth conditions, no change in RuBisCO large subunit levels, no change in RuBisCO carboxylase activity. During sulfur starvation deletion cells are protected against protein degradation. Belongs to the RAF family.