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Real-Time Detection of Single-Molecule DNA Compaction by Condensin I
- Source :
- Current Biology. 14:874-880
- Publication Year :
- 2004
- Publisher :
- Elsevier BV, 2004.
-
Abstract
- Background: Condensin is thought to contribute to large-scale DNA compaction during mitotic chromosome assembly. It remains unknown, however, how the complex reconfigures DNA structure at a mechanistic level. Results: We have performed single-molecule DNA nanomanipulation experiments to directly measure in real-time DNA compaction by the Xenopus laevis condensin I complex. Condensin can bind to the nanomanipulated DNA in the absence of ATP, but it compacts the DNA only in the presence of hydrolyzable ATP. Linear compaction is evidenced by a reduction in the end-to-end extension of nanomanipulated DNA. The reaction results in total compaction of the DNA (i.e., zero end-to-end extension). Discrete and reversible DNA compaction events are observed in the presence of competitor DNA when the DNA is subjected to weak stretching forces ( F = 0.4 picoNewton [pN]). The distribution of step sizes is broad and displays a peak at ∼60 nm (∼180 bp) as well as a long tail. This distribution is essentially unaffected by the topological state of the DNA substrate. Increasing the force to F = 10 pN drives the system toward step-wise reversal of compaction. The distribution of step sizes observed upon disruption of condensin-DNA interactions displays a sharp peak at ∼30 nm (∼90 bp) as well as a long tail stretching out to hundreds of nanometers. Conclusions: The DNA nanomanipulation assay allows us to demonstrate for the first time that condensin physically compacts DNA in an ATP-hydrolysis-dependent manner. Our results suggest that the condensin complex may induce DNA compaction by dynamically and reversibly introducing loops along the DNA.
- Subjects :
- Condensin
Xenopus
Biology
Chromatography, Affinity
General Biochemistry, Genetics and Molecular Biology
Xenopus laevis
chemistry.chemical_compound
Condensin complex
Adenosine Triphosphate
Animals
Nanotechnology
Molecule
Mitosis
Adenosine Triphosphatases
Genetics
Agricultural and Biological Sciences(all)
Biochemistry, Genetics and Molecular Biology(all)
Substrate (chemistry)
DNA
biology.organism_classification
Condensin I complex
DNA-Binding Proteins
chemistry
Multiprotein Complexes
biology.protein
Biophysics
Nucleic Acid Conformation
General Agricultural and Biological Sciences
Subjects
Details
- ISSN :
- 09609822
- Volume :
- 14
- Database :
- OpenAIRE
- Journal :
- Current Biology
- Accession number :
- edsair.doi.dedup.....97de923d060af948cb0f58e92c503384