The functional Hfq-binding module of bacterial sRNAs consists of a double or single hairpin preceded by a U-rich sequence and followed by a 3′ poly(U) tail

(A) Effects of nucleotide substitutions at positions before the terminator hairpin on properties of SgrS. (B) Effects of deletions in the spacer region on properties of SgrS. IT1568 and TM589 cells harboring indicated plasmids were grown in the presence of 0.2% (for preparation of total RNAs) or 1% (for preparation of total proteins) arabinose. Total RNAs and proteins were prepared. RNA samples were subjected to Northern blot analysis using SgrS probe 1 and a ptsG probe. The following amounts of RNAs were loaded: SgrS variants, 0.25 μg; ptsG mRNA, 10 μg. Protein samples equivalent to 0.04 A₆₀₀ units were subjected to Western blot analysis.