The first step toward eukaryotic genome duplication is loading of the replicative helicase onto chromatin. This 'licensing' step initiates with the recruitment of the origin recognition complex (ORC) to chromatin, which is thought to occur via ORC's ATP-dependent DNA binding and encirclement activity. However, we have previously shown that ATP binding is dispensable for the chromatin recruitment of fly ORC, raising the question of how metazoan ORC binds chromosomes.
View Article and Find Full Text PDFMammalian phase II metabolism of dietary plant flavonoid compounds generally involves substitution with glucuronic acid. In contrast, flavonoids mainly exist as glucose conjugates in plants, and few plant UDP-glucuronosyltransferase enzymes have been identified to date. In the model legume Medicago truncatula, the major flavonoid compounds in the aerial parts of the plant are glucuronides of the flavones apigenin and luteolin.
View Article and Find Full Text PDFBotanical supplements derived from grapes are functional in animal model systems for the amelioration of neurological conditions, including cognitive impairment. Rats fed with grape extracts accumulate 3'--methyl-quercetin-3--β-d-glucuronide () in their brains, suggesting as a potential therapeutic agent. To develop methods for the synthesis of and the related 4'--methyl-quercetin-7--β-d-glucuronide (), 3--methyl-quercetin-3'--β-d-glucuronide (), and 4'--methyl-quercetin-3'--β-d-glucuronide (), which are not found in the brain, we have evaluated both enzymatic semisynthesis and full chemical synthetic approaches.
View Article and Find Full Text PDFBoth plant and mammalian cells express glucuronosyltransferases that catalyze glucuronidation of polyphenols such as flavonoids and other small molecules. Oral administration of select polyphenolic compounds leads to the accumulation of the corresponding glucuronidated metabolites at μM and sub-μM concentrations in the brain, associated with amelioration of a range of neurological symptoms. Determining the mechanisms whereby botanical extracts impact cognitive wellbeing and psychological resiliency will require investigation of the modes of action of the brain-targeted metabolites.
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