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- Courtiol-Legourd, Stephanie, et al.
(author)
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Synthesis and kinetic evaluation of phosphomimetic inhibitors targeting type B ribose-5-phosphate isomerase from Mycobacterium tuberculosis
- 2024
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In: Bioorganic & Medicinal Chemistry Letters. - : Elsevier. - 0960-894X .- 1464-3405. ; 102
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Journal article (peer-reviewed)abstract
- Because tuberculosis is still a major health threat worldwide, identification of new drug targets is urgently needed. In this study, we considered type B ribose -5 -phosphate isomerase from Mycobacterium tuberculosis as a potential target, and addressed known problems of previous inhibitors in terms of their sensitivity to hydrolysis catalyzed by phosphatase enzymes, which impaired their potential use as drugs. To this end, we synthesized six novel phosphomimetic compounds designed to be hydrolytically stable analogs of the substrate ribose 5 -phosphate and the best known inhibitor 5-phospho-D-ribonate. The phosphate function was replaced by phosphonomethyl, sulfate, sulfonomethyl, or malonate groups. Inhibition was evaluated on type A and type B ribose -5phosphate isomerases, and stability towards hydrolysis using alkaline phosphatase and veal serum was assessed. One of the phosphomimetic analogs, 5-deoxy-5-phosphonomethyl-D-ribonate, emerged as the first strong and specific inhibitor of the M. tuberculosis enzyme that is resistant to hydrolysis.
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| 2. |
- Mariano, Sandrine, et al.
(author)
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Competitive inhibitors of type B ribose 5-phosphate isomerases : design, synthesis and kinetic evaluation of new D-allose and D-allulose 6-phosphate derivatives
- 2009
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In: Carbohydrate Research. - : Elsevier BV. - 0008-6215 .- 1873-426X. ; 344:7, s. 869-880
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Journal article (peer-reviewed)abstract
- This study reports syntheses Of D-allose 6-phosphate (All6P), D-allulose (or D-psicose) 6-phosphate (Allu6P), and seven D-ribose 5-phosphate isomerase (Rpi) inhibitors. The inhibitors were designed as analogues of the 6-carbon high-energy intermediate postulated for the All6P to Allu6P isomerization reaction (Allpi activity) catalyzed by type B Rpi from Escherichia coli (EcRpiB). 5-PhosphO-D-ribonate, easily obtained through oxidative cleavage of either All6P or Allu6P, led to the original synthon 5-dihydrogenopliospho-D-ribono-1,4-lactone from which the other inhibitors could be synthesized through nucleophilic addition in one step. Kinetic evaluation on Allpi activity of EcRpiB shows that two of these compounds. 5phospho-D-ribonohydroxamic acid and N-(5-phospho-D-ribonoyl)-methylamine, indeed behave as new efficient inhibitors of EcRpiB; further, 5-phospho-D-ribonohydroxamic acid was demonstrated to have competitive inhibition. Kinetic evaluation on Rpi activity of both EcRpiB and RpiB from Mycobacterium tuberculosis (MtRpiB) shows that several of the designed 6-carbon high-energy intermediate analogues are new competitive inhibitors of both RpiBs. One of them, 5-phospho-D-ribonate, not only appears as the strongest competitive inhibitor of a Rpi ever reported in the literature, with a K-i value of 9 mu M for MtRpiB, but also displays specific inhibition of MtRpiB versus EcRpiB.
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| 3. |
- Roos, Annette K., et al.
(author)
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D-ribose-5-phosphate isomerase B from Escherichia coli is also a functional D-allose-6-phosphate isomerase, while the Mycobacterium tuberculosis enzyme is not
- 2008
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In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 382:3, s. 667-679
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Journal article (peer-reviewed)abstract
- Interconversion of D-ribose-5-phosphate (R5P) and D-ribulose-5-phosphate is an important step in the pentose phosphate pathway. Two unrelated enzymes with R5P isomerase activity were first identified in Escherichia coli, RpiA and RpiB. In this organism, the essential 5-carbon sugars were thought to be processed by RpiA, while the primary role of RpiB was suggested to instead be interconversion of the rare 6-carbon sugars D-allose-6-phosphate (All6P) and D-allulose-6-phosphate. In Mycobacterium tuberculosis, where only an RpiB is found, the 5-carbon sugars are believed to be the enzyme's primary substrates. Here, we present kinetic studies examining the All6P isomerase activity of the RpiBs from these two organisms and show that only the E. coli enzyme can catalyze the reaction efficiently. All6P instead acts as an inhibitor of the M. tuberculosis enzyme in its action on R5P. X-ray studies of the M. tuberculosis enzyme co-crystallized with All6P and 5-deoxy-5-phospho-D-ribonohydroxamate (an inhibitor designed to mimic the 6-carbon sugar) and comparison with the E. coli enzyme's structure allowed us to identify differences in the active sites that explain the kinetic results. Two other structures, that of a mutant E. coli RpiB in which histidine 99 was changed to asparagine and that of wild-type M. tuberculosis enzyme, both co-crystallized with the substrate ribose-5-phosphate, shed additional light on the reaction mechanism of RpiBs generally.
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