Photocycloaddition between two adjacent bases in DNA produces a cyclobutane pyrimidine dimer (CPD), which is one of the major UV-induced DNA lesions, with either the cis-syn or trans-syn structure. In this study, we investigated the photosensitized intramolecular cycloaddition of partially-protected thymidylyl-(3'→5')-N(4)-acetyl-2'-deoxy-5-methylcytidine, to clarify the effect of the base modification on the cycloaddition reaction. The reaction resulted in the stereoselective formation of the trans-syn CPD, followed by hydrolysis of the acetylamino group. The same result was obtained for the photocycloaddition of thymidylyl-(3'→5')-N(4)-acetyl-2'-deoxycytidine, whereas both the cis-syn and trans-syn CPDs were formed from thymidylyl-(3'→5')-thymidine. Kinetic analyses revealed that the activation energy of the acid-catalyzed hydrolysis is comparable to that reported for the thymine-cytosine CPD. These findings provided a new strategy for the synthesis of oligonucleotides containing the trans-syn CPD. Using the synthesized oligonucleotide, translesion synthesis by human DNA polymerase η was analyzed.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035463 | PMC |
http://dx.doi.org/10.1093/nar/gkq855 | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China.
Regiodivergent asymmetric synthesis represents a transformative strategy for the efficient generation of structurally diverse chiral products from a single set of starting materials, significantly enriching their enantiomeric composition. However, the design of radical-mediated regiodivergent and enantioselective reactions that can accommodate a wide range of functional groups and substrates has posed significant challenges. The obstacles primarily lie in switching the regioselectivity and achieving high enantiodiscrimination, especially when dealing with high-energy intermediates.
View Article and Find Full Text PDFThe development of new protocols for stereospecific and stereoselective halogenation transformations by mild reaction conditions is a highly desirable research target for the chemical and pharmaceutical industries. Following the straightforward methodology for directly transforming a wide scope of alcohols to alkyl bromides and chlorides using substoichiometric amounts of thioureas and N-halo succinimides (NXS) as a halogen source in a single step, we noticed that in apolar solvents bromination of chiral secondary alcohols did not produce the expected racemates. In this study, the stereochemical aspects of the bromination reaction were examined.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Chemistry, Chemical Engineering, and Biotechnology, Nanyang Technological University, Singapore 637371, Singapore.
Synthetic C-glycosides play a crucial role in molecular biology and medicine. With the surge of interest in C-glycosides and the demand to provide efforts with sufficient feedstock, it is highly significant to pursue novel methodologies to access C-glycosides in a concise and efficient manner. Here, we disclose an attractive strategy that diverges itself from conventional multistep reaction sequences involving the manipulations of protecting groups.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
East China Normal University, School of Chemistry and Molecular Engineering, 3663 N. Zhongshan Rd., 200062, Shanghai, CHINA.
We present a novel electrochemical dicarboxylation of epoxides with CO2, characterized by the cleavage of two C-O single bonds. Not only are vinyl epoxides viable, but cyclic carbonates also serve as effective substrates, facilitating the synthesis of E-configured adipic and octanedioic acids with high chemo-, regio-, and stereoselectivity. The synthetic practicality is further highlighted by the diverse functionalizations of the resulting multifunctional diacids.
View Article and Find Full Text PDFToxins (Basel)
December 2024
Department of Chemistry, University of Ghana, Legon-Accra P.O. Box LG56, Ghana.
Mycolactone is a complex macrolide toxin produced by , the causative agent of Buruli ulcer. The aim of this paper is to review the chemistry, biosynthetic, and synthetic pathways of mycolactone A/B to help develop an understanding of the mode of action of these polyketides as well as their therapeutic potential. The synthetic work has largely been driven by the desire to afford researchers enough (≥100 mg) of the pure toxins for systematic biological studies toward understanding their very high biological activities.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!