Crystallization of a stringent response factor from Aquifex aeolicus.
The crystallization of a key enzyme from Aquifex aeolicus with suggested bifunctional activity, acting as an exopolyphosphatase and a guanosine pentaphosphate phosphohydrolase, is reported. Native data were collected to below 2 A resolution from an orthorhombic crystal with unit-cell parameters a = 50.8, b = 70.3, c = 90.9 A. Methionine residues were introduced by mutation and deliberate oxidation