A study of the thermophilic ribosomal protein S7 binding to the truncated S12-S7 intercistronic region provides more insight into the mechanism of regulation of the str operon of E-coli

A study of the ability of His6-tagged ribosomal protein S7 of Thermus therm ophilus to interact with the truncated S12-S7 intercistronic region of str. mRNA of Escherichia coli has been described, A minimal S7 binding mRNA fra gment is a part of the composite hairpin, with the termination codon of the S12 cistron on one side and the initiation codon of the next S7 cistron on the other. It has a length in the range of 63-103 nucleotides, The 63 nucl eotide mRNA fragment, which corresponds to a putative S7 binding site, bind s very poorly with S7, Tight RNA structure models, which behave as integral systems and link the S7 binding site with the translational regulation reg ion of the hairpin, are suggested, This observation provides more insight i nto the mechanism of S7-directed autogenous control of translational coupli ng of sir. mRNA. (C) 1999 Federation of European Biochemical Societies.