Inhibition of type I and type II phosphomannose isomerases by the reaction intermediate analogue 5-phospho-D-arabinonohydroxamic acid supports a catalytic role for the metal cofactor.
The phosphomannose isomerases (PMI) comprise three families of proteins: type I, type II, and type III PMIs. Members of all three families catalyze the reversible isomerization of D-mannose 6-phosphate (M6P) and D-fructose 6-phosphate (F6P) but share little or no sequence identity. Because (1) PMIs are essential for the survival of several microorganisms, including yeasts and bacteria, and (2) the PMI enzymes from several pathogens do not share significant sequence identity to the human protein, PMIs have been considered as potential therapeutic targets. Elucidation of the catalytic and regulatory mechanisms of the different types of PMIs is strongly needed for rational species-specific drug design. To date, inhibition and crystallographic studies of all PMIs are still largely unexplored. As part of our research program on aldose-ketose isomerases, we report in this paper the evaluation of two new inhibitors of type I and type II PMIs from baker's yeast and Pseudomonas aeruginosa, respectively. We found that 5-phospho-D-arabinonohydroxamic acid (5PAH), which is the most potent inhibitor of phosphoglucose isomerase (PGI), is by far the best inhibitor ever reported of both type I and type II PMI-catalyzed isomerization of M6P to F6P. 5PAH, which has an inhibition constant at least 3 orders of magnitude smaller than that of previously reported PMI inhibitors, may be the first high-energy intermediate analogue inhibitor of the enzymes. We also tested the related molecule 5-phospho-D-arabinonate (5PAA), which is a strong competitive inhibitor of PGI, and found that it does not inhibit either PMI. All together, our results are consistent with a catalytic role for the metal cofactor in PMI activity.
Laboratoire de Chimie Bioorganique et Bioinorganique, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8124, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Bâtiment 420, Université Paris-Sud XI, 91405 Orsay, France.
Céline
C
Roux
Ji Hyun
JH
Lee
Constance J
CJ
Jeffery
Laurent
L
Salmon
D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D001667:Binding, Competitive; D002384:Catalysis; D003067:Coenzymes / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000138:chemical synthesis; D005636:Fructosephosphates / Q000737:chemistry; D005956:Glucose-6-Phosphate Isomerase / Q000037:antagonists & inhibitors / Q000737:chemistry; D006877:Hydroxamic Acids / Q000737:chemistry*; D007536:Isomerism; D007700:Kinetics; D008359:Mannose-6-Phosphate Isomerase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000145:classification; D008360:Mannosephosphates / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D011550:Pseudomonas aeruginosa / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D013403:Sugar Phosphates / Q000737:chemistry*
C456025:5-phosphoarabinonohydroxamic acid; D001426:Bacterial Proteins; D003067:Coenzymes; D004791:Enzyme Inhibitors; D005636:Fructosephosphates; D006877:Hydroxamic Acids; D008360:Mannosephosphates; D008670:Metals; D029701:Saccharomyces cerevisiae Proteins; D013403:Sugar Phosphates; C027693:mannose-6-phosphate; C027618:fructose-6-phosphate; D008359:Mannose-6-Phosphate Isomerase; D005956:Glucose-6-Phosphate Isomerase