In our group, we are working on the biophysical and structural analysis of proteins in the c-di-AMP framework. Within this project we are focussing on the characterization of DHH/DHHA1-type phosphodiesterases that degrade c-di-AMP in two steps, i.e. c-di-AMP → 5’-pApA (step I) carried out by GdpP-type multidomain membrane proteins and 5’-pApA → 2AMP (step II) carried out by soluble phosphodiesterases.

Besides of the lacking structural information of the multidomain protein and the role of the GGDEF and PAS domains, we aim to solve the question why GdpP-type and soluble PDEs have different substrate specificities despite their highly homologous DHH/DHHA1-domains.