Figure 10. Last six reaction steps of the bacterial HSS catalyzed formation of HSP from PUT.

Relevant residues and NAD(H) of HSS, reaction substrates, intermediates, and products are shown as two-dimensional structure representations (see Fig. 3 for distances and orientation in three-dimensional space). The number of each step is indicated by the highlighted (gray background) number of the abstracted reaction circle in the upper left corner. The pK_a,calc-values were calculated with the program PROPKA from the respective structures (steps 11 and 12: BvHSS with PDB ID: 4TVB). The cation-π interaction of Trp-229 is indicated by a thick dashed line. Hydrogen bonds are indicated by thin dotted lines. Delocalized electrons/partial bonds are indicated by thin dashed lines.