Cloning, purification and characterization of the ribosomal protein L11 from E. coli

A high-expression system of L11 was constructed and its interaction with other elements of the ribosome were investigated using physicochemical methods. The gene rplK, coding for the protein L11 from the E. coli 50S ribosomal subunit was amplifyied, cloned and over-expressed. The protein L11 was purified under native and denaturing conditions, refolded and the structures of both proteins were compared. The protein L11 properly refolded from 6 M urea after dialysis. Experiments on binding of proteins L11, RRF and EF-G from Escherichia coli were performed by analytical centrifugation and Biacore. Specific binding between protein L11 and RRF by analytical centrifugation was not detected probably due to structural reasons. These findings may be helpful in the design of new antibiotics that specifically disrupt the interactions in the “GTP-associated site” of the bacterial ribosome, as many of them are not effective anymore. A common intrinsically disordered region of protein L11 was found to be the amino acid sequence 86 97, while the residues 67 74, containing the linker region, are predicted to be disordered by DisEMBL.