RESUMO
OvoA in ovothiol biosynthesis is a mononuclear non-heme iron enzyme catalyzing the oxidative coupling between histidine and cysteine. It can also catalyze the oxidative coupling between hercynine and cysteine, yet with a different regio-selectivity. Due to the potential application of this reaction for industrial ergothioneine production, in this study, we systematically characterized OvoA by a combination of three different assays. Our studies revealed that OvoA can also catalyze the oxidation of cysteine to either cysteine sulfinic acid or cystine. Remarkably, these OvoA-catalyzed reactions can be systematically modulated by a slight modification of one of its substrates, histidine.
Assuntos
Cisteína/análogos & derivados , Metilistidinas/metabolismo , Mycobacterium smegmatis/metabolismo , Betaína/análogos & derivados , Betaína/metabolismo , Catálise , Cisteína/química , Cisteína/metabolismo , Cisteína Dioxigenase/metabolismo , Heme/metabolismo , Histidina/análogos & derivados , Histidina/metabolismo , Humanos , Modelos Biológicos , Estrutura Molecular , Mycobacterium smegmatis/enzimologia , Ressonância Magnética Nuclear Biomolecular , OxirreduçãoRESUMO
A synthesis of natural aculeatin D has been achieved, with the key stereogenic centers taken from inexpensive and readily available D-xylose. In elaboration of D-xylose into a desired form readily applicable in synthesis a previously misinterpreted and overlooked abnormal selectivity in hydroxyl protection was noticed and exploited. Protocols were developed for monotosylation of a triol insoluble in CH2Cl2 and "freezing" the less stable isomer (aculeatin D) at the PIFA-mediated oxidative spirocyclization, respectively. An unexplained deprotonation at a benzyl protecting group by a thermodynamically more stable dithiane carbanion in the literature was also addressed.
