Two 32 base pair, four-arm immobile Holliday junctions have been prepared and studied by two-dimensional 1H nuclear magnetic resonance (NMR) spectroscopy. Two-quantum spectroscopy provides scalar (through bond) correlations for the 1'H, 2'H, and 2''H resonances of the deoxyribose sugar rings and the nonlabile cytosine and thymine base protons. Assignments in the deoxyribose sugars are extended to the 3'H resonances principally from relayed connectivities in total correlation spectra. Severe overlap of resonances in the standard regions of two-dimensional nuclear Overhauser enhancement (NOE) spectra necessitated the use of a unique approach for obtaining sequence-specific assignments of duplex DNA, wherein all possible NOE connectivities in the spectra are analyzed. These studies of 64-residue structures represent a substantial step forward with respect to the size of oligonucleotide for which virtually complete assignments are obtained. The assignments form the critical background for the detailed analysis of Holliday junction structure and dynamics that is required to address key issues in understanding the role of Holliday junctions in genetic recombination and repair.
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http://dx.doi.org/10.1021/bi00217a028 | DOI Listing |
iScience
December 2024
Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China.
AT-rich sequence can cause structure variants such as translocations and its instability can be accelerated by replication stresses. When human 16p11.2 or 22q11.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA.
Long AT repeat tracts form non-B DNA structures that stall DNA replication and cause chromosomal breakage. AT repeats are abundant in human common fragile sites (CFSs), genomic regions that undergo breakage under replication stress. Using an in vivo yeast model system containing AT-rich repetitive elements from human CFS FRA16D, we find that DNA polymerase zeta (Pol ζ) is required to prevent breakage and subsequent deletions at hairpin and cruciform forming (AT/TA)n sequences, with little to no role at an (A/T)28 repeat or a control non-structure forming sequence.
View Article and Find Full Text PDFJ Virol
December 2024
Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Infection by human astrovirus (HAstV), a small, positive-strand RNA virus, is a major cause of gastroenteritis and has been implicated in an increasing number of severe, sometimes fatal, neurological diseases since 2008. Currently, there are no vaccines or antiviral treatments available to treat HAstV infection. An attractive target for antiviral therapeutics is the viral protease due to its essential functions throughout infection.
View Article and Find Full Text PDFSoft Matter
December 2024
Department of Applied Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264006, China.
RSC Adv
November 2024
Institute of Physics, Faculty of Mathematics and Physics, Charles University Ke Karlovu 5, 121 16 Prague 2 Czech Republic +420 95155 1471.
Recently published observations have highlighted the presence of cruciform structures within the genome, suggesting their potential significance in the rapid recognition of the target sequence for transcription factor binding. In this study, we investigate the organization and stability of the (coding) strand within the Serum Response Element of the gene promoter ( SRE), specifically focusing on segments spanning 12 to 36 nucleotides, centered around the CArG-box. Through a thorough examination of UV absorption patterns with varying temperatures, we identified the emergence of a remarkably stable structure, which we conclusively characterized as a hairpin using complementary H NMR experiments.
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