Insight into the role of a novel c-di-GMP effector protein in Rhodococcus ruber.

C-di-GMP is a ubiquitous second messenger in bacterium, which regulates cellular functions such as the formation of biofilm membrane, cell mobility, virulence, cell adhesion, cell cycle et al. These functions are associated with an increasing number of c-di-GMP effector proteins and/or riboswitchs. In the study, CEP1 (c-di-GMP effector protein 1), a novel c-di-GMP binding protein, was screened with a combination of affinity pull-down and LC/MS/MS methods. The binding of CEP1 and c-di-GMP was demonstrated by surface plasmon resonance, with the dissociation constants of 127 ± 1.03 μM. Quantitative real time PCR assay showed the mRNA levels of cep1 gene in R hodococcus ruber SD3 increased to 63.29 times and 71.18 times after toluene and phenol stress, respectively. Furthermore, cep1 gene enhanced strain was constructed using shuttle plasmid pNV18, which showed improved growth compared to the wild-type strain in the presence of different organic solvents. The study provided an insight into a mechanism, by which c-di-GMP was connected with organic solvent tolerance of R hodococcus ruber SD3. • A novel c-di-GMP binding protein was screened and verified in R. ruber SD3. • The c-di-GMP effector was associated with organic solvent tolerance in R. ruber SD3. • Ribosomal protein L22 in R. ruber SD3 was found to be a novel effector protein. [ABSTRACT FROM AUTHOR]