GTPase-Mediated Activation of ATP Sulfurylase
GTP stimulates the synthesis of APS (adenosine 5'-phosphosulfate) by the enzyme ATP sulfurylase (ATP:sulfate adenylyltransferase, EC 220.127.116.11) via a GTPase mechanism. The activation of the enzyme, purified from Escherichia coli, is titratable with GTP. The initial rate of APS formation is increased 116-fold at a saturating concentration of GTP. The enzyme exhibits a GTPase activity that is stimulated by ATP and further enhanced by SO4; however, SO4 alone does not significantly stimulate GTP hydrolysis. The larger subunit of ATP sulfurylase, encoded by cysN, contains a GTP-binding consensus sequence common to other known GTP-binding proteins. This is the first evidence that the sulfate activation pathway is a metabolic target for regulation by a GTPase.
Leyh, T. S.; and Suo, Y.. 1992. GTPase-Mediated Activation of ATP Sulfurylase. Journal of Biological Chemistry. Vol.267(1). 542-545. https://doi.org/10.1016/S0021-9258(18)48528-6 PMID: 1730615 ISSN: 0021-9258