183447-89-4Relevant academic research and scientific papers
Synthesis and Kinetic Evaluation of Inhibitors of the Phosphatidylinositol-Specific Phospholipase C from Bacillus cereus
Matrin, Stephen F.,Wagman, Allan S.
, p. 8016 - 8023 (2007/10/03)
Substrate analogues of phosphatidylinositol (1) were synthesized and evaluated as potential inhibitors of the bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus cereus.The chiral analogues of the water-soluble phospholipid substrate 5 were designed to probe the effects of varying the inositol C-2 hydroxyl group, which generally believed to serve as the nucleophile in the first step of the hydrolysis of phosphatidylinositols by PI-PLC.In the analogues 6-9, the C-2 hydroxyl group on the inositol ring of the phosphatidylinositol derivatives was rationally altered in several ways.Inversion of the stereochemistry at C-2 of the inositol ring led to the scyllo derivative 6.The inositol C-2 hydroxy group was replaced with inversion by a fluorine to produce the scyllo-fluoro inositol 7 and with a hydrogen atom to furnish the 2-deoxy compound 8.The C-2 hydroxyl group was O-methylated to prepare the methoxy derivative 9.The natural inositol configuration at C-2 was retained in the nonhydrolyzable phosphorodithioate analogue 10.The inhibition of PI-PLC by each of these analogues was then analyzed in a continuous assay using D-myo-inositol 1-(4-nitrophenyl phosphate) (25) as a chromogenic substrate.The kinetic parameters for each of these phosphatidylinositol derivatives were determined, and each was found to be a competitive inhibitor with Ki's as follows: 6, 0.2 mM; 10, 0.6 mM; 8, 2.6 mM; 9, 6.6 mM; and 7, 8.8 mM.This study further establishes that the hydrolysis of phosphatidylinositol analogues by bacterial PI-PLC requires not only the presence of a C-2 hydroxyl group on the inositol ring, but the stereochemistry at this position must also correspond to the natural myo-configuration.For future inhibitor design, it is perhaps noteworthy that the best inhibitors 6 and 10 each possess a hydroxyl group at the 2-position.Several of the inhibitors identified in this study are now being used to obtain crystallographic information for an enzyme-inhibitor complex to gain further insights regarding the mechanism of hydrolysis of phosphatidylinositides by this PI-PLC.
