Investigation of the Interaction of Human Origin Recognition Complex Subunit 1 with G-Quadruplex DNAs of Human c-myc Promoter and Telomere Regions |
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Authors: | Afaf Eladl Yudai Yamaoki Shoko Hoshina Haruka Horinouchi Keiko Kondo Shou Waga Takashi Nagata Masato Katahira |
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Affiliation: | 1.Institute of Advanced Energy, Kyoto University, Kyoto 611-0011, Japan; (A.E.); (Y.Y.); (K.K.); (T.N.);2.Graduate School of Energy Science, Kyoto University, Kyoto 606-8501, Japan;3.Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt;4.Department of Chemical and Biological Sciences, Japan Women’s University, Tokyo 112-8681, Japan; (S.H.); (H.H.); (S.W.) |
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Abstract: | Origin recognition complex (ORC) binds to replication origins in eukaryotic DNAs and plays an important role in replication. Although yeast ORC is known to sequence-specifically bind to a replication origin, how human ORC recognizes a replication origin remains unknown. Previous genome-wide studies revealed that guanine (G)-rich sequences, potentially forming G-quadruplex (G4) structures, are present in most replication origins in human cells. We previously suggested that the region comprising residues 413–511 of human ORC subunit 1, hORC1413–511, binds preferentially to G-rich DNAs, which form a G4 structure in the absence of hORC1413–511. Here, we investigated the interaction of hORC1413-511 with various G-rich DNAs derived from human c-myc promoter and telomere regions. Fluorescence anisotropy revealed that hORC1413–511 binds preferentially to DNAs that have G4 structures over ones having double-stranded structures. Importantly, circular dichroism (CD) and nuclear magnetic resonance (NMR) showed that those G-rich DNAs retain the G4 structures even after binding with hORC1413–511. NMR chemical shift perturbation analyses revealed that the external G-tetrad planes of the G4 structures are the primary binding sites for hORC1413–511. The present study suggests that human ORC1 may recognize replication origins through the G4 structure. |
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Keywords: | origin recognition complex G-quadruplex DNA replication replication origin NMR structure |
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