title: Inhibition of glutamate racemase by substrate-product analogues.
abstract: D-Glutamate is an essential biosynthetic building block of the peptidoglycans that encapsulate the bacterial cell wall. Glutamate racemase catalyzes the reversible formation of D-glutamate from L-glutamate and, hence, the enzyme is a potential therapeutic target. We show that the novel cyclic substrate-product analogue (R,S)-1-hydroxy-1-oxo-4-amino-4-carboxyphosphorinane is a modest, partial noncompetitive inhibitor of glutamate racemase from Fusobacterium nucleatum (FnGR), a pathogen responsible, in part, for periodontal disease and colorectal cancer (Ki=3.1±0.6 mM, cf. Km=1.41±0.06 mM). The cyclic substrate-product analogue (R,S)-4-amino-4-carboxy-1,1-dioxotetrahydro-thiopyran was a weak inhibitor, giving only ∼30% inhibition at a concentration of 40 mM. The related cyclic substrate-product analogue 1,1-dioxo-tetrahydrothiopyran-4-one was a cooperative mixed-type inhibitor of FnGR (Ki=18.4±1.2 mM), while linear analogues were only weak inhibitors of the enzyme. For glutamate racemase, mimicking the structure of both enantiomeric substrates (substrate-product analogues) serves as a useful design strategy for developing inhibitors. The new cyclic compounds developed in the present study may serve as potential lead compounds for further development.
authors: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
authors: Mohan
authors: M
authors: Pal
authors: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada. Electronic address: sbearne@dal.ca.
authors: Stephen L
authors: SL
authors: Bearne
mesh_terms: D000591:Amino Acid Isomerases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001412:Bacillus subtilis / Q000201:enzymology; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000378:metabolism; D005673:Fusobacterium / Q000201:enzymology; D018698:Glutamic Acid / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011510:Proteolipids / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D011510:Proteolipids; C036541:phosphate-binding proteolipid; D018698:Glutamic Acid; D000591:Amino Acid Isomerases; C062292:glutamate racemase
keywords: Cyclic glutamate analogue; Fusobacterium nucleatum; Glutamate racemase; Inhibition; Substrate–product analogues; d-Glutamate