
==== Front
bioRxiv
BIORXIV
bioRxiv
2692-8205
Cold Spring Harbor Laboratory

10.1101/2024.08.22.609254
preprint
1
Article
Visualizing Single V-ATPase Rotation Using Janus Nanoparticles
Otomo Akihiro http://orcid.org/0000-0001-6709-4206

Wiemann Jared
Bhattacharyya Swagata
Yamamoto Mayuko
Yu Yan http://orcid.org/0000-0001-6496-5045

Iino Ryota http://orcid.org/0000-0003-0110-5704

22 8 2024
2024.08.22.609254https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://biorxiv.org/lookup/doi/10.1101/2024.08.22.609254
nihpp-2024.08.22.609254.pdf
Understanding the function of rotary molecular motors, such as the rotary ATPases, relies on our ability to visualize the single-molecule rotation. Traditional imaging methods often involve tagging those motors with nanoparticles (NPs) and inferring their rotation from translational motion of NPs. Here, we report an approach using ″two-faced″ Janus NPs to directly image the rotation of single V-ATPase from Enterococcus hirae , an ATP-driven rotary ion pump. By employing a 500-nm silica/gold Janus NP, we exploit its asymmetric optical contrast — silica core with a gold cap on one hemisphere — to achieve precise imaging of the unidirectional counter-clockwise rotation of single V-ATPase motors immobilized on surfaces. Despite the added viscous load from the relatively large Janus NP probe, our approach provides accurate torque measurements of single V-ATPase. This study underscores the advantages of Janus NPs over conventional probes, establishing them as powerful tools for single-molecule analysis of rotary molecular motors.
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pmc
