Corporate Banner
Satellite Banner
Scientific Community
Become a Member | Sign in
Home>News>This Article

Random Walks on DNA

Published: Monday, April 22, 2013
Last Updated: Monday, April 22, 2013
Bookmark and Share
Scientists have revealed how a bacterial enzyme has evolved an energy-efficient method to move long distances along DNA.

The findings, published in Science, present further insight into the coupling of chemical and mechanical energy by a class of enzymes called helicases, a widely-distributed group of proteins, which in human cells are implicated in some cancers.

The new helicase mechanism discovered in this study, led by researchers from the University of Bristol and the Technische Universität Dresden in Germany, may help resolve some of the unexplained roles for helicases in human biology, and in turn help researchers to develop future technological or medical applications.

A commonly held view of DNA helicases is that they move along DNA and “unzip” the double helix to produce single strands of DNA for repair or copying. This process requires mechanical work, so enzyme movement must be coupled to consumption of the chemical fuel ATP. These enzymes are thus often considered as molecular motors.

In the new work, Ralf Seidel and his team at the Technische Universität Dresden developed a microscope that can stretch single DNA molecules whilst at the same time observe the movement of single fluorescently-labelled helicases. In parallel, the Bristol researchers in the DNA-Protein Interactions Unit used millisecond-resolution fluorescence spectroscopy to reveal dynamic changes in protein conformation and the kinetics of ATP consumption.

The team studied a helicase found in bacteria that moves along viral (bacteriophage) DNA. The work demonstrated that, surprisingly, the enzyme only consumed ATP at the start of the reaction in order to change conformation. Thereafter long-range movement along the DNA was driven by thermal motion; in other words by collisions with the surrounding water molecules. This produces a characteristic one-dimensional “random walk” (see picture), where the protein is just as likely to move backwards as forwards.

Mark Szczelkun, Professor of Biochemistry from the University’s School of Biochemistry and one of the senior authors of the study, said: “This enzyme uses the energy from ATP to force a change in protein conformation rather than to unwind DNA. The movement on DNA thereafter doesn’t require an energy input from ATP. Although movement is random, it occurs very rapidly and the enzyme can cover long distances on DNA faster than many ATP-driven motors. This can be thought of as a more energy-efficient way to move along DNA and we suggest that this mechanism may be used in other genetic processes, such as DNA repair.”

The work in Bristol has been funded by the Wellcome Trust through a programme grant to Professor Mark Szczelkun from the School of Biochemistry.

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,800+ scientific posters on ePosters
  • More than 4,000+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Protein Responsible for Controlling Communication Between Brain Cells Identified
Scientists are a step closer to understanding how some of the brain’s 100 billion nerve cells co-ordinate their communication.
Thursday, November 28, 2013
Manipulation of Protein Could Help Stop Spread of Cancer Cells
New findings, published in the Nature journal Oncogene, reveal how a protein, PRH, is normally able to prevent cells from unnecessary migration.
Monday, November 18, 2013
Researchers Find Key to Blood-Clotting Process
Researchers have uncovered a key process in understanding how blood clots form that could help pave the way for new therapies to reduce the risk of heart attacks.
Wednesday, June 26, 2013
Scientific News
Non-Disease Proteins Kill Brain Cells
Scientists at the forefront of cutting-edge research into neurodegenerative diseases such as Alzheimer’s and Parkinson’s have shown that the mere presence of protein aggregates may be as important as their form and identity in inducing cell death in brain tissue.
Closing the Loop on an HIV Escape Mechanism
Research team finds that protein motions regulate virus infectivity.
New Class of RNA Tumor Suppressors Identified
Two short, “housekeeping” RNA molecules block cancer growth by binding to an important cancer-associated protein called KRAS. More than a quarter of all human cancers are missing these RNAs.
Gut Microbes Signal to the Brain When They're Full
Don't have room for dessert? The bacteria in your gut may be telling you something.
Turning up the Tap on Microbes Leads to Better Protein Patenting
Mining millions of proteins could become faster and easier with a new technique that may also transform the enzyme-catalyst industry, according to University of California, Davis, researchers.
Exploring the Causes of Cancer
Queen's research to understand the regulation of a cell surface protein involved in cancer.
Measuring microRNAs in Blood to Speed Cancer Detection
A simple, ultrasensitive microRNA sensor holds promise for the design of new diagnostic strategies and, potentially, for the prognosis and treatment of pancreatic and other cancers.
Novel Proteins Linked to Huntington's Disease
University of Florida Health researchers have made a new discovery about Huntington's disease, showing that the gene that causes the fatal disorder makes an unexpected "cocktail" of mutant proteins that accumulate in the brain.
Enzyme Critical to Maintaining Telomere Length Discovered
New method expected to speed understanding of short telomere diseases and cancer.
New Method Identifies Up to Twice as Many Proteins and Peptides
An international team of researchers developed a method that identifies up to twice as many proteins and peptides in mass spectrometry data than conventional approaches.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,800+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,000+ scientific videos