Reaction: ATP + GTP = 2 diphosphate + cyclic Gp(2'-5')Ap(3'-5') (overall reaction)
(1a) ATP + GTP = pppGp(2'-5')A + diphosphate
(1b) pppGp(2'-5')A = cyclic Gp(2'-5')Ap(3'-5') + diphosphate
Glossary: cyclic Gp(2'-5')Ap(3'-5') = cyclo[(3'→5')-guanylyl-(2'→5')-adenylyl]
Other name(s): cGAMP synthase; cGAS
Systematic name: ATP:GTP adenylyltransferase (cyclizing)
Comments: Cyclic Gp(2'-5')Ap(3'-5') is a signalling molecule in mammalian cells that triggers the production of type I interferons and other cytokines.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:
References:
1. Sun, L., Wu, J., Du, F., Chen, X. and Chen, Z.J. Cyclic GMP-AMP synthase is a cytosolic DNA sensor that activates the type I interferon pathway. Science 339 (2013) 786-791. [PMID: 23258413]
2. Ablasser, A., Goldeck, M., Cavlar, T., Deimling, T., Witte, G., Rohl, I., Hopfner, K.P., Ludwig, J. and Hornung, V. cGAS produces a 2'-5'-linked cyclic dinucleotide second messenger that activates STING. Nature 498 (2013) 380-384. [PMID: 23722158]