The SMC Hinge is a Selective Gate for Obstacle Bypass

Hon Wing Liu, Florian Roisné-Hamelin, Michael Taschner, James Collier, Madhusudhan Srinivasan and Stephan Gruber ()
Additional contact information
Hon Wing Liu: University of Lausanne (UNIL), Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM)
Florian Roisné-Hamelin: University of Lausanne (UNIL), Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM)
Michael Taschner: University of Lausanne (UNIL), Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM)
James Collier: University of Oxford, Department of Biochemistry
Madhusudhan Srinivasan: University of Oxford, Department of Biochemistry
Stephan Gruber: University of Lausanne (UNIL), Department of Fundamental Microbiology (DMF), Faculty of Biology and Medicine (FBM)

Nature Communications, 2025, vol. 16, issue 1, 1-15

Abstract: Abstract DNA loop-extruding SMC complexes play vital roles in genome maintenance and DNA immunity. However, how these ring-shaped DNA motors navigate large DNA-bound obstacles has remained unclear. Here, we demonstrate that a bacterial SMC Wadjet complex can efficiently bypass obstacles larger than the SMC coiled coil lumen when they are tethered to the extruded DNA by a single-stranded DNA or RNA linker. This bypass is mediated by the selective entrapment of the linker within the SMC hinge channel, which functions as an obligate gate—permitting passage of the linker while retaining double-stranded DNA stably inside the SMC ring and keeping associated obstacles outside. We further show that eukaryotic SMC hinges similarly accommodate ssDNA, and that the hinge is dispensable for loop extrusion by Wadjet, altogether suggesting that obstacle bypass represents the conserved, long-sought function of the SMC hinge toroid. By integrating hinge bypass with loop extrusion, we provide a mechanistic framework for how DNA-entrapping SMC complexes can generate chromosomal loops densely decorated with obstacles.

Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/s41467-025-65408-5 Abstract (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:natcom:v:16:y:2025:i:1:d:10.1038_s41467-025-65408-5

Ordering information: This journal article can be ordered from
https://www.nature.com/ncomms/

DOI: 10.1038/s41467-025-65408-5

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

More articles in Nature Communications from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().