Navigation Links
Random walks on DNA
Date:4/19/2013

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 Universitt 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 Universitt 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."


'/>"/>

Contact: Caroline Clancy
caroline.clancy@bristol.ac.uk
44-011-792-88086
University of Bristol
Source:Eurekalert

Related biology news :

1. Random Forests Tree Ensembles: Salford Systems Exclusive Insight
2. Far from random, evolution follows a predictable genetic pattern, Princeton researchers find
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/13/2017)... SAN FRANCISCO , Feb. 13, 2017 /PRNewswire/ ... a centralized platform that is designed to enhance ... the latest release in the RSA Fraud & ... to enable organizations to leverage additional insights from ... anti-fraud tools to better protect their customers from ...
(Date:2/9/2017)... 9, 2017 The biomass boiler market report ... biomass boiler market globally in terms of revenue (US$ ... The market for biomass boilers has been segmented on ... and country/region. The market based on feedstock type, has ... biogas & energy crops, urban residues, and others. On ...
(Date:2/8/2017)... YORK , Feb. 7, 2017 Report Highlights ... The ... should reach $11.4 billion by 2021, growing at a compound ... Includes - An overview of the global markets for synthetic ... 2015, estimates for 2016, and projections of compound annual growth ...
Breaking Biology News(10 mins):
(Date:2/23/2017)... Capitol Hill neighborhood, with its swanky shops, parks and cafés, might ... salon to set up shop. But there,s Hair Fairies ... on E Madison Ave, and CEO Maria Botham ... we pride ourselves on being a destination for parents and ... associated with lice. Everyone can get lice – it doesn,t ...
(Date:2/23/2017)... ... February 23, 2017 , ... Today, researchers can fast-track ... uric acid, and/or other biomarkers or SNPs of interest) using one, easy-to-collect saliva ... , the relationship between insulin and other relevant biomarkers can be extensively studied ...
(Date:2/23/2017)... (PRWEB) , ... February 22, 2017 , ... ... and photonics , have been named Fellows of the Society this year, the ... contributions in the multidisciplinary fields of optics, photonics, and imaging as well as ...
(Date:2/22/2017)... , Feb. 22, 2017 Scientists propose in ... and organ damage in Gaucher and maybe other lysosomal ... and lower costs than current therapies. An ... Medical Center , which also included investigators from the ... report their data Feb. 22. The study was conducted ...
Breaking Biology Technology: