Complexes of the enzyme phosphomannomutase/phosphoglucomutase with a slow substrate and an inhibitor

Two complexes of the enzyme phosphomannomutase/phosphoglucomutase (PMM/PGM) from Pseudomonas aeruginosa with a slow substrate and with an inhibitor have been characterized by X-ray crystallography. Both ligands induce an interdomain rearrangement in the enzyme that creates a highly buried active site. Comparisons with enzyme-substrate complexes show that the inhibitor xylose 1-phosphate utilizes many of the previously observed enzyme-ligand interactions. In contrast, analysis of the ribose 1-phosphate complex reveals a combination of new and conserved enzyme-ligand interactions for binding. The ability of PMM/PGM to accommodate these two pentose phosphosugars in its active site may be relevant for future efforts towards inhibitor design.