ジャーナル: Nucleic Acids Res / 年: 2025 タイトル: Amyloid-like DNA bridging: a new mode of DNA shaping. 著者: Frank Wien / Marcos Gragera / Tatsuhito Matsuo / Gautier Moroy / María Teresa Bueno-Carrasco / Rocío Arranz / Antoine Cossa / Anne Martel / Heloisa N Bordallo / Svemir Rudić / Marisela ...著者: Frank Wien / Marcos Gragera / Tatsuhito Matsuo / Gautier Moroy / María Teresa Bueno-Carrasco / Rocío Arranz / Antoine Cossa / Anne Martel / Heloisa N Bordallo / Svemir Rudić / Marisela Velez / Johan R C van der Maarel / Judith Peters / Véronique Arluison / 要旨: All organisms depend on specific proteins to compact and organize their genomes. In eukaryotes, histones fulfil this role, while bacterial chromosomes are shaped by nucleoid-associated proteins (NAPs) ...All organisms depend on specific proteins to compact and organize their genomes. In eukaryotes, histones fulfil this role, while bacterial chromosomes are shaped by nucleoid-associated proteins (NAPs). Among its pleiotropic functions, the NAP Hfq plays a pivotal role in bacterial genome organization. In this study, we characterized the structure of the C-terminal extension of Hfq, which mediates chromosomal compaction, in its DNA-bound state. Using an integrative approach that combined transmission electron microscopy, neutron scattering, site-directed mutagenesis, and molecular modeling, we identified an amyloid module formed by the C-terminal region of Hfq. This module uniquely bridges and compacts six DNA molecules, marking the first documented instance of an amyloid structure with DNA-bridging properties. Our findings redefine the functional landscape of amyloids, linking them to genome architecture and gene regulation. This result suggests that amyloid-DNA interactions may represent a conserved mechanism across biological systems, with profound implications for understanding genome organization and the regulation of gene expression in both prokaryotes and eukaryotes.
名称: DNA (dA:dT)59 / タイプ: dna / ID: 2 詳細: Double stranded (ds) DNA sequence: (dA:dT)59. The choice of this 59-basepair homo-polymeric DNA sequence was made because Hfq has highest affinity for A-rich sequences. 分類: DNA
モデル: Quantifoil R2/2 / 材質: COPPER/RHODIUM / メッシュ: 300 / 前処理 - タイプ: GLOW DISCHARGE / 前処理 - 時間: 30 sec. / 前処理 - 雰囲気: AIR / 詳細: 25 mA
凍結
凍結剤: ETHANE / チャンバー内湿度: 95 % / チャンバー内温度: 277.15 K / 装置: FEI VITROBOT MARK IV
詳細
The sample consisted in the amyloid structure formed by Hfq CTR region (38 amino acid residues) bound to a double stranded (ds) DNA sequence: (dA:dT)59 prepared in water at 20 mg/mL and then diluted. The molar ratio DNA:CTR was 4:1 (DNA concentration expressed in base-pair). Samples were analyzed after 4 weeks to allow complex full self-assembly.
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電子顕微鏡法
顕微鏡
TFS TALOS
撮影
フィルム・検出器のモデル: FEI FALCON III (4k x 4k) 平均電子線量: 40.0 e/Å2