Fig. 2.

The asymmetric structure of the open hDDC dimer. The upper part of the figure schematically illustrates the two asymmetric monomers of the open structures of hDDC (Red—chain-B, open conformation; Purple—chain-A, intermediate conformation; see also Fig. S3) and the PLP occupancy in the four alternative conformations observed for the active site in the three structures of hDDC obtained before (structure 1) and after soaking (structure 2 and 3). Each conformation is shown with different colors and ordered (from A to E) as illustrated in the scheme, going from the open to the closed monomer (Blue—holo-pkDDC, pdb id: 1js6) and from 0 to 1 PLP occupancy. The lower part of the figure shows a stick representation of the side chains of the active site residues in the five alternative conformations, including the closed conformation. The colors used in each box from A to E are the same of the upper scheme. Throughout the boxes a dashed line indicates the position of the backbone residues of loop1: Red—apo state; Blue—holo state.