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:3/27/2017)... March 27, 2017  Catholic Health Services (CHS) ... Systems Society (HIMSS) Analytics for achieving Stage 6 ... sm . In addition, CHS previously earned a ... using an electronic medical record (EMR). ... level of EMR usage in an outpatient setting.  ...
(Date:3/23/2017)... PUNE, India , March 23, 2017 The report ... Equipment, Touchless Biometric), Industry, and Geography - Global Forecast to 2022", published by ... growing at a CAGR of 29.63% between 2017 and 2022. ... ... Logo ...
(Date:3/22/2017)... 2017 Optimove , provider of ... such as 1-800-Flowers and AdoreMe, today announced two ... Replenishment. Using Optimove,s machine learning algorithms, these features ... replenishment recommendations to their customers based not just ... customer intent drawn from a complex web of ...
Breaking Biology News(10 mins):
(Date:9/19/2017)... , ... September 19, 2017 , ... ... largest group of funded early-stage tech companies. “Grit” author Angela Duckworth and her ... joining the ic@3401 community is Cooley, an international law firm with decades of ...
(Date:9/19/2017)... ... 2017 , ... The new and improved Oakton® pocket testers, from Cole-Parmer, stand ... with a new cap design that is versatile, functional and leakproof. They are ideal ... test water quality. , The Oakton pocket testers have many user-friendly and functional features. ...
(Date:9/19/2017)... , Sept. 19, 2017 ValGenesis Inc., ... (VLMS) is pleased to announce the strategic partnership with ... provide clients with validation services using the latest technology ... VTI will provide clients with efficient and cost-effective validation ... marketing partner for the ValGenesis VLMS system. ...
(Date:9/19/2017)... ... 2017 , ... Molecular Devices, LLC, a leader in protein ... the CloneSelect™ Single-Cell Printer™ in North America. This novel system utilizes sophisticated ... documentation of monoclonality for use in cell line development. , Clonal cell ...
Breaking Biology Technology: