GGDEF domain-containing enzymes are diguanylate cyclases that produce cyclic di-GMP (cdiG), a second messenger that modulates the key bacterial lifestyle transition from a motile to sessile biofilm-forming state. The ubiquity of genes encoding GGDEF proteins in bacterial genomes has established the dominance of cdiG signaling in bacteria. A subfamily of GGDEF enzymes synthesizes the asymmetric signaling molecule cyclic AMP-GMP. Hybrid CDN-producing and promiscuous substrate-binding (Hypr) GGDEF enzymes are widely distributed and found in other deltaproteobacteria and have roles that include regulation of cAG signaling. GGDEF enzymes that produce cyclic dinucleotides are especially of interest.
UC Berkeley researcher have developed a new method of preparing and using cyclic dinucleotides (CDNs) by contacting a CDN producing-enzyme (e.g., a GGDEF enzyme) with a precursor of a CDN under conditions sufficient to convert the precursor into a CDN. This method produces a variety of non-naturally occurring, asymmetric and symmetric CDNs and can be performed in vitro or in a genetically modified host cell. Also provided are CDN compositions that find use in a variety of applications such as modulating an immune response in an individual.