The stability of DNA ends generated by the HO endonuclease in yeast is surprisingly high with a half-life of more than an hour. This transient stability is unaffected by mutations that abolish nonhomologous end joining (NHEJ). The unprocessed ends interact with Yku70p and Yku80p, two proteins required for NHEJ, but not significantly with Rad52p, a protein involved in homologous recombination (HR). Repair of a double-strand break by NHEJ is unaffected by the possibility of HR, although the use of HR is increased in NHEJ-defective cells. Partial in vitro 5' strand processing suppresses NHEJ but not HR. These results show that NHEJ precedes HR temporally, and that the availability of substrate dictates the particular pathway used. We propose that transient stability of DNA ends is a foundation for the permanent stability of telomeres.
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http://dx.doi.org/10.1016/s1097-2765(02)00705-0 | DOI Listing |
Nat Commun
January 2025
School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, 100081, China.
Designing asymmetrical structures is an effective strategy to optimize metallic catalysts for electrochemical carbon dioxide reduction reactions. Herein, we demonstrate a transient pulsed discharge method for instantaneously constructing graphene-aerogel supports asymmetric copper nanocluster catalysts. This process induces the convergence of copper atoms decomposed by copper chloride onto graphene originating from the intense current pulse and high temperature.
View Article and Find Full Text PDFNat Commun
January 2025
Shanghai Key Laboratory MFree, Institute for Shanghai Advanced Research in Physical Sciences, Shanghai, 201203, China.
In recent years, metal hydride research has become one of the driving forces of the high-pressure community, as it is believed to hold the key to superconductivity close to ambient temperature. While numerous novel metal hydride compounds have been reported and extensively investigated for their superconducting properties, little attention has been focused on the atomic and electronic states of hydrogen, the main ingredient in these novel compounds. Here, we present combined H- and La-NMR data on lanthanum superhydrides, LaH, (x = 10.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.
The polycrystalline nature of perovskites, stemming from their facile solution-based fabrication, leads to a high density of grain boundaries (GBs) and point defects. However, the impact of GBs on perovskite performance remains uncertain, with contradictory statements found in the literature. We developed a machine learning force field, sampled GB structures on a nanosecond time scale, and performed nonadiabatic (NA) molecular dynamics simulations of charge carrier trapping and recombination in stoichiometric and doped GBs.
View Article and Find Full Text PDFSci Adv
January 2025
State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China.
Hong-Ou-Mandel (HOM) interference is the foundation of quantum optics to test the degree of indistinguishability of two incoming photons, playing a key role in quantum communication, sensing, and photonic quantum computing. Realizing high-visibility HOM interference with massively parallel optical channels is challenging due to the lack of available natural optical references for aligning independent arrayed laser pairs. Here, we demonstrate 50 parallel comb-teeth pairs of continuous-wave weak coherent photons HOM interference using two independently frequency post-aligned soliton microcombs (SMCs), achieving an average fringe visibility over 46%.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Single-Molecule and Cell Mechanobiology Laboratory, Daejeon, 34141, South Korea.
Helicase is a nucleic acid motor that catalyses the unwinding of double-stranded (ds) RNA and DNA via ATP hydrolysis. Helicases can act either as a nucleic acid motor that unwinds its ds substrates or as a chaperone that alters the stability of its substrates, but the two activities have not yet been reported to act simultaneously. Here, we used single-molecule techniques to unravel the synergistic coordination of helicase and chaperone activities, and found that the severe acute respiratory syndrome coronavirus helicase (nsp13) is capable of two modes of action: (i) binding of nsp13 in tandem with the fork junction of the substrate mechanically unwinds the substrate by an ATP-driven synchronous power stroke; and (ii) free nsp13, which is not bound to the substrate but complexed with ADP in solution, destabilizes the substrate through collisions between transient binding and unbinding events with unprecedented melting capability.
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