Guanosine‐5′‐triphosphate regulates the interaction between MciZ and FtsZ

Abstract

MciZ, a 40 amino acid peptide, is known to express during bacterial sporulation in Bacillus subtilis cells. MciZ has been shown to inhibit the assembly of FtsZ and guanosine‐5′‐triphosphate (GTP) has been shown to reduce the effect of MciZ‐induced inhibition of FtsZ assembly. In this study, we showed that MciZ directly interacts with FtsZ in vitro with a dissociation constant of 0.3 ± 0.1 μM. Using several complementary techniques, we provide evidence suggesting that GTP inhibits the binding of FtsZ to MciZ. Interestingly, GTP inhibited the binding of MciZ to FtsZ more strongly than GDP. The overexpression of MciZ in heterologous E. coli cells perturbed the Z‐ring formation, inhibited bacterial cell division and caused elongation of E. coli cells. Subsequently, we found that N‐terminal 19 residue peptide (M19I) of MciZ interacted with FtsZ in vitro and inhibited FtsZ polymerization. M19I reduced the GTPase activity of FtsZ. Based on these results; we suggest that GTP plays an important role in interaction of MciZ to FtsZ and that M19I may be considered as an initial lead towards designing a peptide inhibitor of FtsZ assembly that acts by inhibiting GTP binding to FtsZ.