Functional implication of the sole arginine residue of ribosomal proteins L7/L12.

Modification of the only arginine residue present in proteins L7/L12 from Escherichia coli with phenylglyoxal, 2,3-butanedione and 1,2-cyclohexanedione is accompanied by functional alterations. The capacity of these proteins to promote polyphenylalanine synthesis and elongation factor G-dependent hydrolysis of GTP in L7/L12-depleted ribosomal cores is significantly decreased (more than 50%) on modification. Incubation of the butanedione- and cyclohexanedione-modified L7/L12 under regenerating conditions is accompanied by recovery of the original activity in polyphenylalanine synthesis. These results and the conservation of the arginine residue in eubacterial L7/L12-type proteins point to the functional implication of this arginine residue.