Replication protein A (RPA) is a single-stranded DNA binding protein that plays an essential role in telomere maintenance. RPA binds to and unfolds G-quadruplex (G4) structures formed in telomeric DNA, thus facilitating lagging strand DNA replication and telomerase activity. To investigate the effect of G4 stability on the interactions with human RPA (hRPA), we used a combination of biochemical and biophysical approaches. Our data revealed an inverse relationship between G4 stability and ability of hRPA to bind to telomeric DNA; notably small G4 ligands that enhance G4 stability strongly impaired G4 unfolding by hRPA. To gain more insight into the mechanism of binding and unfolding of telomeric G4 structures by RPA, we carried out photo-crosslinking experiments to elucidate the spatial arrangement of the RPA subunits along the DNA strands. Our results showed that RPA1 and RPA2 are arranged from 5' to 3' along the unfolded telomeric G4, as already described for unstructured single-stranded DNA, while no contact is possible with RPA3 on this short oligonucleotide. In addition, these data are compatible with a 5' to 3' directionality in G4 unfolding by hRPA.
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http://dx.doi.org/10.1016/j.biochi.2014.04.006 | DOI Listing |
Nat Commun
December 2024
Architecture and Dynamics of Biological Macromolecules, Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Paris, France.
Replication Protein A (RPA) plays a pivotal role in DNA replication by coating and protecting exposed single-stranded DNA, and acting as a molecular hub that recruits additional replication factors. We demonstrate that archaeal RPA hosts a winged-helix domain (WH) that interacts with two key actors of the replisome: the DNA primase (PriSL) and the replicative DNA polymerase (PolD). Using an integrative structural biology approach, combining nuclear magnetic resonance, X-ray crystallography and cryo-electron microscopy, we unveil how RPA interacts with PriSL and PolD through two distinct surfaces of the WH domain: an evolutionarily conserved interface and a novel binding site.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, PR China.
Accurate and sensitive fluorescence imaging of biothiols is essential for understanding the mechanism underlying some physiological and pathological events, as well as the prevention and diagnosis of diseases. However, low signal transduction efficiency and poor biocompatibility of fluorescence tags associated with current sensors hinder their potential utilizations. Herein, a smart biothiols sensitive vivo imaging platform on the basis of amplifying nanoprobe has been designed.
View Article and Find Full Text PDFVirology
December 2024
Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, 310018, Hangzhou, China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, 310018, Hangzhou, China. Electronic address:
Late expression factor 3 (LEF3), a multifunctional single-stranded DNA binding protein encoded by baculoviruses, is indispensable for viral DNA replication and plays a pivotal role in viral infection. Our previous quantitative analysis of phosphorylomics revealed that the phosphorylation levels of two serine residues (S8 and S25) located in LEF3 nuclear localization sequence were significantly up-regulated after Bombyx mori nucleopolyhedrovirus (BmNPV) infection, but the underlying mechanism remained unknown. To investigate the impact of phosphorylation on BmNPV infection, site-direct mutagenesis was performed on LEF3 to obtain phosphorylated mimic (S/D) or dephosphorylated mimic (S/A) mutants.
View Article and Find Full Text PDFBMC Vet Res
December 2024
Department of Research, Research and Development Station for Bovine, Arad, Romania.
Background: There are no studies belong NOTCH2 gene polymorphism in relation to reproductive and productive traits in Holstein cattle. The objective of the present study was to investigate the effect of NOTCH2 gene polymorphisms on productive and reproductive performance of fertile and anestrum cattle.
Methods: The cattle were classified into anestrus for 3-12 months postpartum (n = 115, 37.
Biomater Adv
December 2024
Department of Chemistry and the Natural Science Research Institute, Myongji University, 116 Myongji-ro, Yongin-si 17058, Republic of Korea. Electronic address:
MicroRNAs (miRNAs) are non-coding, endogenous small single-stranded RNA molecules involved in post-transcriptional regulation of gene expression. It has been demonstrated that dysregulation of miRNA plays a major role in tumor formation, proliferation, and metastasis. Therefore, the delivery of anti-miRNA oligonucleotides to block the activity of these oncogenic miRNAs is a high-potential anti-cancer therapy approach.
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