Dna Helicase
Dna Helicase - Related Videos
00:55
DNA Helicases
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2020
DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...
07:37
Single-Molecule Real-Time Visualization of DNA Unwinding by CMG Helicase
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Cited by 1 •
2024
This protocol demonstrates performing a single-molecule assay for live visualization of DNA unwinding by CMG helicase. It describes (1) preparing a DNA substrate, (2) purifying fluorescently labeled Drosophila melanogaster CMG helicase, (3) preparing a microfluidic flow cell for total internal reflection fluorescence (TIRF) microscopy, and (4) the single-molecule DNA unwinding assay.
04:10
Helicase Activity Measurement of a Target Protein Using Biotin-Labeled RNA Duplexes
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2025
In this video, we demonstrate the procedure to determine the helicase activity of a target protein to unwind the biotin-labeled dsRNA substrate. The activity of the enzyme was identified by analyzing the electrophoretic mobility shift, followed by a chemiluminescence assay using chemiluminescent enzyme-conjugated streptavidin.
02:40
DNA Replication
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2020
DNA replication involves the separation of the two strands of the double helix, with each strand serving as a template from which the new complementary strand is copied. After replication, each double-stranded DNA includes one parental or “old” strand and one “new” strand. This is known as semiconservative replication. The resulting DNA molecules have the same sequence and are divided equally into the two daughter cells. Replication in Prokaryotes DNA replication uses a large number of...
01:02
The DNA Replication Fork
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2020
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
FAQs
ATP hydrolysis supplies the energy for conformational changes in DNA helicase. These structural shifts allow the enzyme to move along one DNA strand and disrupt the hydrogen bonding between complementary bases. Because strand separation depends on this energy-coupled movement, changes in ATP use or helicase conformational cycling can directly affect access to the genetic information needed for replication.
Strand separation alone does not duplicate a genome. DNA helicase opens the replication fork, while primase and DNA polymerase participate in the coordinated copying process. Their cooperation links the production of accessible single-stranded templates with the synthesis of new DNA. This coordination helps replication proceed as an integrated process rather than as unrelated enzymatic activities.
Movement along one DNA strand gives helicase a directional way to advance the replication fork. As the enzyme progresses, it repeatedly exposes additional genetic information for copying. This ongoing activity is important because replication requires access to the DNA template across the genome, not merely separation at one initial location.
By controlling access to DNA during replication and related maintenance processes, helicase activity supports accurate preservation of genetic information. Its function is also connected with DNA repair and recombination, which help cells manage damaged or rearranged DNA. When helicase activity is defective, these maintenance pathways may be disrupted, contributing to chromosome instability and disease.
Researchers examine helicase structure and function to understand how it binds DNA, uses ATP, moves along a strand, and opens the replication fork. They also consider its cooperation with primase, DNA polymerase, and other replication proteins. This combined perspective connects molecular mechanism with the larger process of accurate genome duplication.
Related helicase activities support DNA repair and recombination in addition to genome replication. These processes use access to DNA in different maintenance contexts, including the handling of genetic information that must be corrected or rearranged. Studying these activities helps explain how cells preserve genome integrity and why defects in helicase enzymes can have broader biological consequences.