Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Light-scattering studies on supercoil unwinding.

A M Campbell, D J Jolly

    The Biochemical Journal
    |June 1, 1973
    PubMed
    Summary
    This summary is machine-generated.

    Supercoiled DNA unwinds from a Y-shape to a toroid and then a circle as temperature or dye concentration increases. These structural changes challenge the conventional straight interwound model of supercoiled DNA.

    Related Concept Videos

    You might also read

    Related Articles

    Articles linked to this work by shared authors, journal, and citation graph.

    Sort by
    Same author

    Social-pair judgment bias testing in slow-growing broiler chickens raised in low- or high-complexity environments.

    Scientific reports·2023
    Same author

    Impact of environmental complexity and stocking density on affective states of rainbow trout (Oncorhynchus mykiss).

    Animal cognition·2022
    Same author

    Environmental complexity positively impacts affective states of broiler chickens.

    Scientific reports·2021
    Same author

    Cross-reactivity of anti-dsDNA antibodies.

    Immunology today·2014
    Same author

    Multispecific monoclonal antibodies.

    Immunology today·2014
    Same author

    [Not Available].

    Immunology today·2014

    Area of Science:

    • Molecular Biology
    • Biophysics
    • Structural Biology

    Background:

    • Supercoiled DNA structure is crucial for various biological processes.
    • Previous studies suggested a Y-shape for supercoiled bacteriophage DNA at specific conditions.

    Purpose of the Study:

    • To investigate the structural transitions of supercoiled DNA upon unwinding.
    • To determine the tertiary and secondary structure changes resulting from alterations in superhelix density.

    Main Methods:

    • Utilized temperature changes to unwind supercoiled DNA.
    • Employed the intercalating dye proflavine to induce unwinding.
    • Analyzed structural changes using root-mean-square radius and particle-scattering factor P(theta).

    Main Results:

    Related Experiment Videos

    • DNA maintained a Y-shape across a range of superhelix densities (sigma) with temperature changes.
    • Significant structural changes occurred at sigma=-0.0176 (74.5°C), indicated by reduced root-mean-square radius and altered P(theta).
    • Proflavine-induced unwinding revealed transitions to toroid (sigma=-0.018) and circular (sigma=-0.0004) structures.

    Conclusions:

    • Supercoiled DNA undergoes significant structural transitions beyond the Y-shape upon unwinding.
    • The observed structures (toroid, circle) are incompatible with the conventional straight interwound model.
    • This study provides new insights into the dynamic structural plasticity of supercoiled DNA.