ジャーナル: Proc Natl Acad Sci U S A / 年: 2025 タイトル: Dimeric gold nanoparticles enable multiplexed labeling in cryoelectron tomography. 著者: Hoyoung Kim / Cathy J Spangler / Aya Matsui / Johannes Elferich / Junhoe Kim / Alex Roseborough / May Nyman / Tanja M Lahtinen / Eric Gouaux / 要旨: Cryoelectron tomography (cryo-ET) enables three-dimensional visualization of molecular structures within tissue and intact cells, providing a powerful tool for studying the spatial organization of ...Cryoelectron tomography (cryo-ET) enables three-dimensional visualization of molecular structures within tissue and intact cells, providing a powerful tool for studying the spatial organization of biological components at nanometer resolution. Realizing this potential, particularly for submegadalton complexes, is facilitated by fiducial-based labeling. Gold nanoparticles (AuNPs) have emerged as powerful electron-dense labels for cryo-ET, but multiplexing using only conventional monomeric AuNPs is challenging, limiting their application in multitarget studies. Here, we describe functionalized dimeric AuNPs with a precisely defined size range applied to bioimaging, enabling multiplexed labeling by allowing reliable discrimination between monomeric and dimeric AuNPs, thereby supporting identification of distinct molecular targets within the same cryotomogram. Each dimer consists of two covalently linked gold particles of approximately 2.6 nm diameter separated by a defined spacing of about 1.4 nm, with high structural homogeneity validated by small-angle X-ray scattering (SAXS) and electron microscopy. The anti-GluN1 Fab, which targets the -methyl-D-aspartate receptor (NMDAR), was site specifically conjugated to a dimeric AuNP. A deep learning classifier enabled reliable discrimination between monomeric and dimeric AuNPs in tomograms. We confirmed that the dimeric AuNP-Fab conjugates bind robustly to recombinant GluN1/GluN2A receptors, validating their use for structural labeling. In situ cryo-ET of brain tissue further confirms that the dimeric labels reach NMDARs within the glutamatergic synaptic cleft. Combined with monomeric AuNPs, this dimeric AuNP platform establishes a generalizable approach for distinguishable labels optimized for cryo-ET. The compact size and structural uniformity of monomeric and dimeric AuNPs make them ideally suited for nanoscale molecular mapping in crowded cellular environments.
装置: OTHER 詳細: The value given for _em_high_pressure_freezing.instrument is Leica ICE. This is not in a list of allowed values {'LEICA EM PACT2', 'LEICA EM PACT', 'BAL-TEC HPM 010', 'EMS-002 RAPID IMMERSION ...詳細: The value given for _em_high_pressure_freezing.instrument is Leica ICE. This is not in a list of allowed values {'LEICA EM PACT2', 'LEICA EM PACT', 'BAL-TEC HPM 010', 'EMS-002 RAPID IMMERSION FREEZER', 'OTHER', 'LEICA EM HPM100'} so OTHER is written into the XML file.
Cryo protectant
20 % dextran /5 % sucrose
切片作成
集束イオンビーム - 装置: OTHER / 集束イオンビーム - イオン: OTHER / 集束イオンビーム - 電圧: 30 / 集束イオンビーム - 電流: 0.03 / 集束イオンビーム - 時間: 120 / 集束イオンビーム - 温度: 83 K / 集束イオンビーム - Initial thickness: 40000 / 集束イオンビーム - 最終 厚さ: 200 集束イオンビーム - 詳細: The value given for _em_focused_ion_beam.instrument is TFS Aquilos 2. This is not in a list of allowed values {'DB235', 'OTHER'} so OTHER is written into the XML file.
位置合わせマーカー
Manufacturer: Gikd nanoparticle / 直径: 10 nm
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電子顕微鏡法
顕微鏡
TFS KRIOS
撮影
フィルム・検出器のモデル: GATAN K3 BIOCONTINUUM (6k x 4k) 平均電子線量: 50.0 e/Å2