• Cryogenic single-molecule fluorescence imaging

    Photophysical behaviors of single fluorophores at low temperatures. (A) Intensity profiles of EGFP fused with streptavidin binding protein at room temperature (red) and 77 K (blue), with 20 averaged trajectories. EGFP exhibited prolonged fluorescence at 77 K, remaining active for over 180 s, compared to photobleaching 10 s at room temperature. (B) Intensity profile of a single fluorophore conjugated to DNA, showing severe photoblinking at 77 K (blue), contrasted with the more stable intensity profile of Cy3 on DNA at room temperature.
  • Single-molecule perspectives of CRISPR/Cas systems: target search, recognition, and cleavage

    DNA-targeting CRISPR/Cas systems. DNA-targeting CRISPR/Cas systems operate in three stages, based on distinct targeting mechanisms. (A) Type I involves Cascade, which identifies PAM and recruits Cas3 for DNA nicking along a single strand. (B) In Type II, Cas9 pairs with crRNA, locates PAM, and induces blunt dsDNA breaks by aligning its HNH and RuvC domains. (C) Type V uses Cas12 with a crRNA guide to recognize PAM, cleaving the non-target strand first, followed by the target strand through the RuvC domain, which after a staggered dsDNA break is formed, remains active for further ssDNA cleavage.
  • Single-molecule studies of repair proteins in base excision repair

    Short-patch and long-patch BER pathways. The figure illustrates the short-and long-patch pathways of BER. In both pathways, a DNA glycosylase initiates the repair by recognizing and removing a damaged base, leaving an AP site. APE1 subsequently cleaves the DNA backbone at the AP site, resulting in a single-strand break. In the short-patch pathway (left), XRCC1 forms a complex with Pol β and LIG3 to replace the damaged nucleotide and seal the nick. In the long-patch pathway (right), PCNA and PARP1 are recruited to the repair site. Pol δ/ε extends the repair patch by displacing the damaged strand. FEN1 then cleaves the displaced flap, and LIG1 seals the remaining nick to complete the repair.
  • Dynamics of nucleosomes and chromatin fibers revealed by single-molecule measurements

    Single-molecule tools to study nucleosome dynamics. The single-molecule techniques that have been used to study nucleosome dynamics are shown in schematic, which techniques include magnetic tweezers, optical tweezers, smFRET measurements, and AFM imaging. Created in BioRender. Kim, H. (2025) https://BioRender.com/e61y533.

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Current Issue

January 2025
Volume 58
Issue 1

2023 SCI Impact Factor 2.9

BIOCHEMISTRY & MOLECULAR BIOLOGY 178/313

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