[Show abstract][Hide abstract] ABSTRACT: Here we show that bis(3'-5') cyclic diadenylic acid (c-di-AMP) and a diadenylate cyclase (DAC) domain protein involved in the biosynthesis of c-di-AMP were identified in Streptococcus pyogenes. The matrix-assisted laser desorption ionization (MALDI)-time of flight (TOF) mass spectrum of the cell extract of S. pyogenes, which showed a fragment pattern very similar to that of the authentic sample of c-di-AMP, revealed that S. pyogenes produces c-di-AMP in the cell. Subsequently, we confirmed by an in vitro experiment that the production of c-di-AMP in the cell is due to the action of Spy1036 gene encoding a DAC domain protein named spyDAC, which is a new protein different from a well-known diadenylate cyclase. Moreover, the experiment gave a product with a molecular weight of 657.021, which is consistent with the molecular weight of c-di-AMP. Furthermore, the mass spectral fragment pattern of the product obtained by the in vitro biosynthesis is quite similar to that of the product produced by the above in vivo experiment. This in vitro production of c-di-AMP indicated that spyDAC in S. pyogenes actually catalyzes the in vivo biosynthesis of c-di-AMP from ATP.
Nagoya journal of medical science 02/2011; 73(1-2):49-57.
[Show abstract][Hide abstract] ABSTRACT: Cyclic bis(3'-5')diguanylic acid (cyclic-di-GMP) functions as a second messenger in diverse species of bacteria to trigger wide-ranging physiological changes. We measured cyclic-di-GMP and its structural analogs such as cyclic bis(3'-5')guanylic/adenylic acid (cyclic-GpAp), cyclic bis(3'-5')guanylic/inosinic acid (cyclic-GpIp) and monophosphorothioic acid of cyclic-di-GMP (cyclic-GpGps) for effects on the biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa. We constructed a knockout mutant of SA0701, which is a GGDEF motif protein relevant to diguanylate cyclase from S. aureus 2507. We confirmed that the biofilm formation of this mutant (MS2507 Delta SA0701) was reduced. Cyclic-di-GMP corresponding to physiological intracellular levels given in the culture recovered the biofilm formation of MS2507 Delta SA0701, whereas its analogs did not, indicating that unlike a previous suggestion, cyclic-di-GMP was involved in the positive regulation of the biofilm formation of S. aureus and its action was structurally specific. At a high concentration (200 microM), cyclic-di-GMP and its analogs showed suppression effects on the biofilm formation of S. aureus and P. aeruginosa, and according to the quantification study using costat analysis, the suppression potential was in the order of cyclic-di-GMP, cyclic-GpGps, cyclic-GpAp and cyclic-GpIp, suggesting that the suppression effect was not strictly specific and the change of base structure quantitatively affected the suppression activity.