The Enzymatic Decarboxylation Mechanism of 5-Carboxy Uracil: A Comprehensive Quantum Chemical Study.

Dynamic regulation of DNA methylation is an important process for the control of gene expression in mammals. It is believed that in the demethylation pathway of 5-methyl cytosine, the intermediate 5-carboxy cytosine () can be actively decarboxylated alongside the substitution in the base excision repair. For the active decarboxylation of , a decarboxylase has not been identified so far.

Range-Separated Density-Functional Theory in Combination with the Random Phase Approximation: An Accuracy Benchmark.

A formulation of range-separated random phase approximation (RPA) based on our efficient ω-CDGD-RI-RPA [ , , 2505] method and a large scale benchmark study are presented. By application to the GMTKN55 data set, we obtain a comprehensive picture of the performance of range-separated RPA in general main group thermochemistry, kinetics, and noncovalent interactions. The results show that range-separated RPA performs stably over the broad range of molecular chemistry included in the GMTKN55 set.

Oxidative Ring Contraction of Cyclobutenes: General Approach to Cyclopropylketones including Mechanistic Insights.

An original oxidative ring contraction of easily accessible cyclobutene derivatives for the selective formation of cyclopropylketones (CPKs) under atmospheric conditions is reported. Comprehensive mechanistic studies are proposed to support this novel, yet unusual, rearrangement. Insights into the mechanism ultimately led to simplification and generalization of the ring contraction of cyclobutenes using mCPBA as an oxidant.

Base-Independent DNA Base-Excision Repair of 8-Oxoguanine.

Living organisms protect their genome from gene mutation by excising damaged DNA bases. Here, 8-oxoguanine (8OG) is one of the most abundant DNA lesions. In bacteria the base excision is catalyzed by the enzyme formamidopyrimidine-DNA- glycosylase (Fpg), for which two different orientations of 8OG binding into the active site of Fpg have been proposed: syn- and anti-conformation.