2,4-Diaminopyrimidine (trivially K) and imidazo[1,2-a]-1,3,5-triazine-2(8H)-4(3H)-dione (trivially X) form a nucleobase pair with Watson-Crick geometry as part of an artificially expanded genetic information system (AEGIS). Neither K nor X can form a Watson-Crick pair with any natural nucleobase. Further, neither K nor X has an accessible tautomeric form or a protonated/deprotonated state that can form a Watson-Crick pair with any natural nucleobase. In vitro experiments show how DNA polymerase I from E. coli manages replication of DNA templates with one K:X pair, but fails with templates containing two adjacent K:X pairs. In analogous in vivo experiments, E. coli lacking dKTP/dXTP cannot rescue chloramphenicol resistance from a plasmid containing two adjacent K:X pairs. These studies identify bacteria able to serve as selection environments for engineering cells that replicate AEGIS pairs that lack forms that are Watson-Crick complementary to any natural nucleobase.
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http://dx.doi.org/10.1021/acssynbio.6b00193 | DOI Listing |
Rapid Commun Mass Spectrom
April 2025
Solar System Exploration Division, NASA Goddard Space Center, Greenbelt, Maryland, USA.
Rationale: Extraterrestrial amines and ammonia are critical ingredients for the formation of astrobiologically important compounds such as amino acids and nucleobases. However, conventional methods for analyzing the composition and isotopic ratios of volatile amines suffer from lengthy derivatization and purification procedures, high sample mass consumption, and chromatographic interferences from derivatization reagents and non-target compounds.
Methods: Here we demonstrate a highly efficient method to analyze the composition and compound specific isotopic ratios of C to C amines as well as ammonia based on solid phase micro-extraction (SPME) on-fiber derivatization.
Bioorg Chem
January 2025
Department of Chemistry, Sarojini Naidu College for Women, Kolkata 700028, India. Electronic address:
Peptide nucleic acids (PNA), synthetic molecules comprising a peptide-like backbone and natural and unnatural nucleobases, have garnered significant attention for their potential applications in gene editing and other biomedical fields. The unique properties of PNA, particularly enhanced stability/specificity/affinity towards targeted DNA and RNA sequences, achieved significant attention recently for gene silencing, gene correction, antisense therapy, drug delivery, biosensing and other various diagnostic aspects. This review explores the structure, properties, and potential of PNA in transforming genetic engineering including potent biomedical challenges.
View Article and Find Full Text PDFCell Death Dis
January 2025
Tianjian Laboratory of Advanced Biomedical Sciences, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China.
Mitochondrial oxidative phosphorylation (OXPHOS) is a therapeutic vulnerability in glycolysis-deficient cancers. Here we show that inhibiting OXPHOS similarly suppresses the proliferation and tumorigenicity of glycolytically competent colorectal cancer (CRC) cells in vitro and in patient-derived CRC xenografts. While the increased glycolytic activity rapidly replenished the ATP pool, it did not restore the reduced production of aspartate upon OXPHOS inhibition.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
School of the Chemical Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
The folding of the guanine repetitive region in the telomere unit into G-quadruplex (G4) by drugs has been suggested as an alternative approach for cancer therapy. Hydroxychloroquine (HCQ) and chloroquine (CQ) are two important drugs in the trial stage for cancer. Both drugs can induce the folding of telomere-guanine-rich sequences into G4 even in the absence of salt.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia.
Apurinic/apyrimidinic (AP) sites are endogenous DNA lesions widespread in human cells. Having no nucleobases, they are noncoding and promutagenic. AP site repair is generally initiated through strand incision by AP endonuclease 1 (APE1).
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