Everything that has a beginning, has an end.
After six years of research we can finally show how a riboswitch interacts with the ribosome. Thanks to Vanessa and all other people involved for their endurance and enthusiasm on this project.
Translational riboswitches are cis-acting RNA regulators that modulate the expression of genes during translation initiation. Their mechanism is considered as an RNA-only gene-regulatory system inducing a ligand-dependent shift of the population of functional ON- and OFF-states.
"Our data challenges the “RNA-only” model of riboswitch function, as translational regulation only occurs upon concerted yet dynamic interaction of mRNA, 30S ribosomes and associated modulator proteins."
For the adenine-sensing riboswitch from Vibrio vulnificus we can show that ligand binding alone is not sufficient for switching to a translational ON-state but the interaction of the riboswitch with the 30S ribosome is indispensable. Only the synergy of binding of adenine and of 30S ribosome, in particular protein rS1, induces complete opening of the translation initiation region.
To read the full the story: 10.1038/s41467-021-25024-5