Disruptions of Genes Encoding Ribose-5-Phosphate Isomerases in Increases Sensitivity of Bacteria to Antibiotics.

In cells, the main enzymes involved in pentose interconversion are ribose-5-phosphate isomerases RpiA and RpiB and ribulose-5-phosphate epimerase Rpe. The inactivation of limits ribose-5-phosphate (R5P) synthesis via the oxidative branch of the pentose phosphate pathway (PPP) and unexpectedly results in antibiotic supersensitivity. This type of metabolism is accompanied by significant changes in the level of reducing equivalents of NADPH and glutathione, as well as a sharp drop in the ATP pool.

Crystallization and preliminary X-ray study of Vibrio cholerae uridine phosphorylase in complex with 6-methyluracil.

Uridine phosphorylase catalyzes the phosphorolysis of ribonucleosides, with the nitrogenous base and ribose 1-phosphate as products. Additionally, it catalyzes the reverse reaction of the synthesis of ribonucleosides from ribose 1-phosphate and a nitrogenous base. However, the enzyme does not catalyze the synthesis of nucleosides when the substrate is a nitrogenous base substituted at the 6-position, such as 6-methyluracil (6-MU).

Expression, purification, crystallization and preliminary X-ray structure analysis of Vibrio cholerae uridine phosphorylase in complex with thymidine.

A high-resolution structure of the complex of Vibrio cholerae uridine phosphorylase (VchUPh) with its physiological ligand thymidine is important in order to determine the mechanism of the substrate specificity of the enzyme and for the rational design of pharmacological modulators. Here, the expression and purification of VchUPh and the crystallization of its complex with thymidine are reported. Conditions for crystallization were determined with an automated Cartesian Dispensing System using The Classics, MbClass and MbClass II Suites crystallization kits.