The Interaction Between Primer Synthase DnaG And C-di-GMP Synthase Ms2196 In Mycobacterium Smegmatis

c-di-GMP is an important second messenger, which plays an important role in the regulation of cells mobility, virulence, surface adhesion, cell cycle, cell differentiation, cell adapt to the environment and long-term survival et al. However, the relationship between c-di-GMP and DNA replication has not been reported. In Mycobacterium smegmatis, c-di-GMP was synthesized and degraded by Ms2196, which was found to interact physically with primer synthase DnaGMsm in this study. Furthermore, c-di-GMP was found to be bound by DnaGMsm.The results of this study are as follows:(1) We characterized the physical interaction between DnaGMsm and Ms2196 by bacterial two-hybrid assay, Pull-down assay, co-immunoprecipitation assay and Surface plasmon resonance assay. (2) We characterized the interaction between C-terminal domain of DnaGMsm and N-terminal domain of Ms2196 using bacterial two-hybrid assay, Pull-down assay and surface plasmon resonance assay. (3) By UV cross-linking experiments, DnaGMsm was found to bind with the second messenger molecule c-di-GMP, which is the product of Ms2196. (4) c-di-GMP and GTP could competitively bind to DnaGMsm, and DnaGMsm might have two sites for c-di-GMP binding.In this study, we demonstrated the interaction between DnaGMsm and Ms2196 for the first time which will help to our understanding about DNA replication regulation of Mycobacterium smegmatis and the function of bacterial second messenger molecule c-di-GMP.