Diadenylate cyclase explained

diadenylate cyclase
Ec Number:	2.7.7.85
Width:	270

Diadenylate cyclase, DNA integrity scanning protein DisA is a DNA binding protein^[1] participates in a DNA-damage check-point. DisA forms globular foci that rapidly scan along the chromosomes searching for lesions. Catalytic activity

2 ATP

\rightleftharpoons

2 diphosphate + cyclic di-3',5'-adenylate.

This enzyme has diadenylate cyclase activity, catalyzing the condensation of 2 ATP molecules into cyclic di-AMP (c-di-AMP). c-di-AMP likely acts as a signaling molecule that may couple DNA integrity with a cellular process. This rate-limiting step is the accessibility of the active site; mutating the possible exit tunnel (residues 128-130) increases product 2-fold despite Arg-130 being important for ATP-binding. Does not convert GTP to c-di-GMP.

Notes and References

Witte G, Hartung S, Büttner K, Hopfner KP . Structural biochemistry of a bacterial checkpoint protein reveals diadenylate cyclase activity regulated by DNA recombination intermediates . Molecular Cell . 30 . 2 . 167–78 . April 2008 . 18439896 . 10.1016/j.molcel.2008.02.020 . free .