The RBCX protein has been identified as having a possible chaperone-like function [1]. The rbcX gene is juxtaposed to and cotranscribed with rbcL and rbcS encoding RuBisCO in Anabaena sp. CA [2]. RbcX has been shown to possess a chaperone-like function assisting correct folding of RuBisCO in E. coli expression studies and is needed for RuBisCO to reach its maximal activity [2].

1: Evolution of cyanobacteria by exchange of genetic material among phyletically related strains. Rudi K, Skulberg OM, Jakobsen KS; J Bacteriol 1998;180:3453-3461. PMID:9642201

2: Maximum activity of recombinant ribulose 1,5-bisphosphate carboxylase/oxygenase of Anabaena sp. strain CA requires the product of the rbcX gene. Li LA, Tabita FR; J Bacteriol 1997;179:3793-3796. PMID:9171433