The Cys319 loop modulates the transition between dehydrogenase and hydrolase conformations in inosine 5'-nophosphate dehydrogenase

The effects of Ala substitutions at three residues of the Cys319 loop, Arg322, Glu323 and Gln324 are described. The experiments have shown that the Cys319 loop has different conformations during the dehydrogenase and hydrolase reactions and also that the structure of the Cys319 loop has modulated the closure of the mobile flap.