Practical enzymatic synthesis of 3′,3′-cGAMP

A mutant-type 3′,3′-cGAMP synthase comprising a by-production reducing mutation and a high activity mutation, wherein the by-production reducing mutation is one or more amino acid mutations selected from the group consisting of the following amino acid residues:

• Y117, N121, M130, K177, A292, and K350 of wild-type 3′,3′-cGAMP synthase consisting of SEQ ID NO:
• 1, the high activity mutation is one or more amino acid mutations selected from the group consisting of the following amino acid residues:
• R44, E146, H170, L211, E342 and S346 of wild-type 3′,3′-cGAMP synthase consisting of SEQ ID NO:
• 1, the by-production reducing mutation contains at least one mutation selected from the group consisting of the following amino acid residues:
• Y117 (H, R, or K), N121 (1, G, A, V, L, or P), M130 (V, I, G, A, L, P, F, H, Y, or W), K177 (M, H, C, F, Y, or W), A292 (T, K, Y, S, F, W, R, or H), and K350 (E, D, M, N, O, or C), and the mutant-type 3′,3′-cGAMP synthase reduces by-productions of c-di-GMP and c-di-AMP in 3′,3′-cGAMP synthesis reaction and enhances 3′,3′-cGAMP synthesis activity in comparison with the wild-type 3′,3′-cGAMP synthase consisting of SEQ ID NO:
• 1, the high activity mutation enhances the 3′,3′-cGAMP synthesis activity, the by-production reducing mutation reduces the by-productions of c-di-GMP and c-di-AMP, and the high activity mutation contains at least one mutation selected from the group consisting of the following amino acid residues:
• R44H, E146D, H170P, L211P, E342K and S346P, and the mutant-type 3′,3′-cGAMP synthase further comprises an amino acid mutation L413P of wild-type 3′,3′-cGAMP synthase consisting of SEQ ID NO:
• 1.