RbcX can function as a Rubisco-chaperonin, but is non essential in Synechococcus PCC7942

Abstract

In most cyanobacteria, the gene rbcX is co-transcribed with the rbcL and rbcS genes that code for the large and small subunits of ribulose-1,5- bisphosphate carboxylase/oxygenase (Rubisco). Previous co-expression studies in Escherichia coli of cyanobacterial Rubisco and RbcX have identified a chaperonin-like function for RbcX. The organization of the rbcLXS operon has, to a certain extent, precluded definitive gene function studies of rbcX in cyanobacteria. In Synechococcus PCC7942, however, rbcX is located >100 kb away from the rbcLS operon, providing an opportunity to examine the role of RbcX by insertional inactivation without interference from the Rubisco genes. Fully segregated Synechococcus PCC7942 ΔrbcX Show more