“…In their typical mechanism, structural changes of the aptamer domain directly modulate the secondary structure of the neighboring expression platform, structural changes of which then result in either translational control to mask or unmask the ribosome‐binding sequence (RBS) or transcriptional control to close or open the terminator (or antiterminator) stem‐loop. Such structural changes have been characterized or proposed for several riboswitches, including two adenine riboswitches ( ydhL and add , Serganov et al., ), xpt guanine riboswitch (Serganov et al., ), thiM TPP riboswitch (Winkler, Nahvi, & Breaker, ), yitJ SAM‐I riboswitch (Shahbabian, Jamalli, Zig, & Putzer, ), Enterococcus faecalis SAM‐III riboswitch (Price, Grigg, & Ke, ) and lysC lysine riboswitch (Sudarsan, Wickiser, Nakamura, Ebert, & Breaker, ), the expression platforms of which are all <40 nt in length. Putative riboswitches can also be identified through functional outcomes in expression of downstream ORFs or the confirmation of their aptamer domain structures.…”