Dynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediates

Abstract The sequence specificity and programmability of DNA binding and cleavage have enabled widespread applications of CRISPR-Cas12a in genetic engineering. As an RNA-guided CRISPR endonuclease, Cas12a engages a 20-base pair (bp) DNA segment by forming a three-stranded R-loop structure in which t...

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Main Authors: Kevin D. P. Aris, Joshua C. Cofsky, Honglue Shi, Noor Al-Sayyad, Ivan E. Ivanov, Ashwin Balaji, Jennifer A. Doudna, Zev Bryant
Format: Article
Language:English
Published: Nature Portfolio 2025-03-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-57703-y
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author Kevin D. P. Aris
Joshua C. Cofsky
Honglue Shi
Noor Al-Sayyad
Ivan E. Ivanov
Ashwin Balaji
Jennifer A. Doudna
Zev Bryant
author_facet Kevin D. P. Aris
Joshua C. Cofsky
Honglue Shi
Noor Al-Sayyad
Ivan E. Ivanov
Ashwin Balaji
Jennifer A. Doudna
Zev Bryant
author_sort Kevin D. P. Aris
collection DOAJ
description Abstract The sequence specificity and programmability of DNA binding and cleavage have enabled widespread applications of CRISPR-Cas12a in genetic engineering. As an RNA-guided CRISPR endonuclease, Cas12a engages a 20-base pair (bp) DNA segment by forming a three-stranded R-loop structure in which the guide RNA hybridizes to the DNA target. Here we use single-molecule torque spectroscopy to investigate the dynamics and mechanics of R-loop formation of two widely used Cas12a orthologs at base-pair resolution. We directly observe kinetic intermediates corresponding to a ~5 bp initial RNA-DNA hybridization and a ~17 bp intermediate preceding R-loop completion, followed by transient DNA unwinding that extends beyond the 20 bp R-loop. The complex multistate landscape of R-loop formation is ortholog-dependent and shaped by target sequence, mismatches, and DNA supercoiling. A four-state kinetic model captures essential features of Cas12a R-loop dynamics and provides a biophysical framework for understanding Cas12a activity and specificity.
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institution Kabale University
issn 2041-1723
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series Nature Communications
spelling doaj-art-bcbc1dc16ce444c29f5a04d08c8a12a02025-08-20T03:53:32ZengNature PortfolioNature Communications2041-17232025-03-0116111310.1038/s41467-025-57703-yDynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediatesKevin D. P. Aris0Joshua C. Cofsky1Honglue Shi2Noor Al-Sayyad3Ivan E. Ivanov4Ashwin Balaji5Jennifer A. Doudna6Zev Bryant7Biophysics Program, Stanford UniversityDepartment of Molecular and Cell Biology, University of California, BerkeleyHoward Hughes Medical Institute, University of California, BerkeleyDepartment of Bioengineering, Stanford UniversityDepartment of Bioengineering, Stanford UniversityBiophysics Program, Stanford UniversityDepartment of Molecular and Cell Biology, University of California, BerkeleyDepartment of Bioengineering, Stanford UniversityAbstract The sequence specificity and programmability of DNA binding and cleavage have enabled widespread applications of CRISPR-Cas12a in genetic engineering. As an RNA-guided CRISPR endonuclease, Cas12a engages a 20-base pair (bp) DNA segment by forming a three-stranded R-loop structure in which the guide RNA hybridizes to the DNA target. Here we use single-molecule torque spectroscopy to investigate the dynamics and mechanics of R-loop formation of two widely used Cas12a orthologs at base-pair resolution. We directly observe kinetic intermediates corresponding to a ~5 bp initial RNA-DNA hybridization and a ~17 bp intermediate preceding R-loop completion, followed by transient DNA unwinding that extends beyond the 20 bp R-loop. The complex multistate landscape of R-loop formation is ortholog-dependent and shaped by target sequence, mismatches, and DNA supercoiling. A four-state kinetic model captures essential features of Cas12a R-loop dynamics and provides a biophysical framework for understanding Cas12a activity and specificity.https://doi.org/10.1038/s41467-025-57703-y
spellingShingle Kevin D. P. Aris
Joshua C. Cofsky
Honglue Shi
Noor Al-Sayyad
Ivan E. Ivanov
Ashwin Balaji
Jennifer A. Doudna
Zev Bryant
Dynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediates
Nature Communications
title Dynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediates
title_full Dynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediates
title_fullStr Dynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediates
title_full_unstemmed Dynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediates
title_short Dynamic basis of supercoiling-dependent DNA interrogation by Cas12a via R-loop intermediates
title_sort dynamic basis of supercoiling dependent dna interrogation by cas12a via r loop intermediates
url https://doi.org/10.1038/s41467-025-57703-y
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