Figure 6.
Proposed catalytic pathway for AtMAPDA. (A) In the apo state, the zinc ion adopts a hexa-coordination state with an open conformation. (B) The substrate binds and induces the conformational transformation to a closed one and a trigonal bipyramidal geometry accordingly. (C) Asp295 activates Wcat for the SN2 reaction and a tetrahedral intermediate forms. (D) The methylamine leaves to finish the reaction and trigonal bipyramidal geometry is reproduced. (E) AMP is released and the enzyme goes back to the open state and the octahedral geometry. The open states were placed to the left of the dashed line whereas the closed states were to the right.