dorsal/arxiv
View SchemaVelocity and processivity of helicase unwinding of double-stranded nucleic acids
| Authors | M. D. Betterton, Frank Julicher |
|---|---|
| Categories | |
| ArXiv ID | physics/0509138 |
| URL | https://arxiv.org/abs/physics/0509138 |
| DOI | 10.1088/0953-8984/17/47/015 |
| Journal | Journal of Physics: Condensed Matter 17 (2005) S3851--S3869 |
Abstract
Helicases are molecular motors which unwind double-stranded nucleic acids (dsNA) in cells. Many helicases move with directional bias on single-stranded (ss) nucleic acids, and couple their directional translocation to strand separation. A model of the coupling between translocation and unwinding uses an interaction potential to represent passive and active helicase mechanisms. A passive helicase must wait for thermal fluctuations to open dsNA base pairs before it can advance and inhibit NA closing. An active helicase directly destabilizes dsNA base pairs, accelerating the opening rate. Here we extend this model to include helicase unbinding from the nucleic-acid strand. The helicase processivity depends on the form of the interaction potential. A passive helicase has a mean attachment time which does not change between ss translocation and ds unwinding, while an active helicase in general shows a decrease in attachment time during unwinding relative to ss translocation. In addition, we describe how helicase unwinding velocity and processivity vary if the base-pair binding free energy is changed.
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"abstract": "Helicases are molecular motors which unwind double-stranded nucleic acids\n(dsNA) in cells. Many helicases move with directional bias on single-stranded\n(ss) nucleic acids, and couple their directional translocation to strand\nseparation. A model of the coupling between translocation and unwinding uses an\ninteraction potential to represent passive and active helicase mechanisms. A\npassive helicase must wait for thermal fluctuations to open dsNA base pairs\nbefore it can advance and inhibit NA closing. An active helicase directly\ndestabilizes dsNA base pairs, accelerating the opening rate. Here we extend\nthis model to include helicase unbinding from the nucleic-acid strand. The\nhelicase processivity depends on the form of the interaction potential. A\npassive helicase has a mean attachment time which does not change between ss\ntranslocation and ds unwinding, while an active helicase in general shows a\ndecrease in attachment time during unwinding relative to ss translocation. In\naddition, we describe how helicase unwinding velocity and processivity vary if\nthe base-pair binding free energy is changed.",
"arxiv_id": "physics/0509138",
"authors": [
"M. D. Betterton",
"Frank Julicher"
],
"categories": [
"physics.bio-ph",
"cond-mat.soft",
"q-bio.BM"
],
"doi": "10.1088/0953-8984/17/47/015",
"journal_ref": "Journal of Physics: Condensed Matter 17 (2005) S3851--S3869",
"title": "Velocity and processivity of helicase unwinding of double-stranded nucleic acids",
"url": "https://arxiv.org/abs/physics/0509138"
},
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