Cyclic di-GMP-I riboswitches are a class of riboswitch that specifically bind cyclic di-GMP,[1] which is a second messenger that is used in a variety of microbial processes including virulence, motility and biofilm formation.

Cyclic di-GMP-I riboswitches were originally identified by bioinformatics as a conserved RNA-like structure called the "GEMM motif".

The discovery of this riboswitch class answers the question of how genes are regulated in response to cyclic di-GMP levels in many different bacteria.

The two classes of cyclic di-GMP-binding riboswitches do not share any known sequence or structural features.

High-resolution three-dimensional structures of cyclic di-GMP-I riboswitches have been determined using X-ray crystallography.