DNA glycosylases are key enzymes in the first step of base excision DNA repair, recognizing DNA damage and catalyzing the release of damaged nucleobases. Bifunctional DNA glycosylases also possess associated apurinic/apyrimidinic (AP) lyase activity that nick the damaged DNA strand at an abasic (or AP) site, formed either spontaneously or at the first step of repair. NEIL1 is a bifunctional DNA glycosylase capable of processing lesions, including AP sites, not only in double-stranded but also in single-stranded DNA. Here, we show that proteins participating in DNA damage response, YB-1 and RPA, affect AP site cleavage by NEIL1. Stimulation of the AP lyase activity of NEIL1 was observed when an AP site was located in a 60 nt-long double-stranded DNA. Both RPA and YB-1 inhibited AP site cleavage by NEIL1 when the AP site was located in single-stranded DNA. Taking into account a direct interaction of YB-1 with the AP site, located in single-stranded DNA, and the high affinity of both YB-1 and RPA for single-stranded DNA, this behavior is presumably a consequence of a competition with NEIL1 for the DNA substrate. Xeroderma pigmentosum complementation group C protein (XPC), a key protein of another DNA repair pathway, was shown to interact directly with AP sites but had no effect on AP site cleavage by NEIL1.
Despite the remarkable resistance of the nucleic acid phosphodiester backbone to degradation affording genetic stability, the P-O bond must be broken during DNA repair and RNA metabolism, among many other critical cellular processes. Nucleases are powerful enzymes that can enhance the uncatalyzed rate of phosphodiester bond cleavage by up to ∼10-fold. Despite the most well accepted hydrolysis mechanism involving two metals (M to activate a water nucleophile and M to stabilize the leaving group), experimental evidence suggests that some nucleases can use a single metal to facilitate the chemical step, a controversial concept in the literature.
The isoquinoline core is present in one of the largest subsets of bioactive natural products. The multifunctional isoquinoline core exerts diverse bioactivity, resulting in the development of numerous isoquinoline-based drugs and molecules that are currently under clinical trials. We developed a new approach for phosphite-mediated [1,2] alkyl migration for an overall -C-H alkylation -alkylation of isoquinoline.
In Nature, the four-electron reduction of O is catalyzed at preorganized multimetallic active sites. These complex active sites often feature low-coordinate, redox-active metal centers precisely positioned to facilitate rapid O activation processes that obviate the generation of toxic, partially reduced oxygen species. Very few biomimetic constructs simultaneously recapitulate the complexity and reactivity of these biological cofactors.
Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei, People's Republic of China; Department of Clinical Laboratory, Anhui Public Health Clinical Center, Hefei, People's Republic of China. Electronic address:
Since Candida albicans, a type of fungus, causes severe infections that pose a significant threat to human health, its rapid detection is critical in clinical antifungal therapy. Traditional fungal diagnostic approaches are largely based on the culture method. This method is time-consuming and laborious, taking about 48-72 h, and cannot identify emerging species, making it unsuitable for critically ill patients with bloodstream infections, sepsis, and so on.
Glucose transporter 4 (GLUT4) expression on white adipocytes is critical for absorbing excess blood glucose, failure of which promotes hyperglycemia. Matrix metalloproteinases (MMPs) play a crucial role in remodeling the white adipose tissue (WAT) during obesity. MMPs have multiple protein substrates, and surprisingly, it is unknown if they can directly target GLUT4 on the adipocyte surface and impair glucose absorption.
