HOME >> BIOLOGY >> NEWS
Surprise finding for stretched DNA

BERKELEY, CA -- Most of us are familiar with the winding staircase image of DNA, the repository of a biological cell's genetic information. But few of us realize just how tightly that famous double helix is wound. Stretched to its full length, a single molecule of human DNA extends more than three feet, but, when wound up inside the nucleus of a cell, that same molecule measures about one millionth of an inch across. Biologists have long believed that as a molecule of DNA is stretched, its double helix starts to unwind. As much sense as this makes from an intuitive standpoint, a recent experiment proved it not to be the case.

Researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley used a combination of microscopic beads and magnetic tweezers to observe that when a DNA molecule is stretched, it actually begins to overwind. This overwinding continues until the force being applied to stretch the DNA exceeds about 30 picoNewtons. (One picoNewton is about a trillionth the force required to hold an apple against Earth's gravity.) Beyond the 30 picoNewton threshold, the DNA double helix did begin to unwind in accordance with predictions.

"DNA's helical structure implies that twisting and stretching should be coupled, hence the prediction that DNA should unwind when stretched," said biophysicist Carlos Bustamante, who led this experiment. "That is why it was such surprise when we directly measured twist-stretch coupling to find instead DNA overwinds when stretched. The DNA molecule, when studied at close range, continues to surprise us!"

Bustamante is a leading authority on the use of single-molecule visualization and manipulation techniques to study the dynamics, structure and kinetics of molecular motors and nucleo-protein assemblies. He holds joint appointments with Berkeley Lab's Physical Biosciences Division and UC Berkeley's Departments of Mo
'"/>

Contact: Lynn Yarris
lcyarris@lbl.gov
510-486-5375
DOE/Lawrence Berkeley National Laboratory
7-Aug-2006


Page: 1 2 3

Related biology news :

1. Surprise! Computer scientists model the exclamation point
2. New findings challenge established views on human genome
3. New findings challenge established views about human genome
4. Depiction of findings selected as 2007 Image of the Year by Society for Nuclear Medicine
5. LIAI scientists make important finding on cytomegalovirus transmission
6. New findings in smell and taste
7. Study produces conflicting findings on the use of anti-anemia drug in cancer patients
8. Bloods clotting cells harbor ticking time bombs, finding may help extend blood supply
9. Stress and nerve cells survival in rats; finding may open window for depression treatment
10. CMU researcher publishes anole lizard findings
11. Surprising airbag hazards among research findings at hearing safety conference

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:8/21/2020)... (PRWEB) , ... August 19, 2020 , ... ... Salimetrics LLC and SalivaBio LLC, businesses dedicated to Salivary Bioscience for more than ... the recently published book by Springer, " Salivary Bioscience: Foundations of Interdisciplinary Saliva ...
(Date:8/21/2020)... ... August 20, 2020 , ... NDA Partners Chairman ... Operations executive with expertise in clinical trial planning and feasibility, regulatory inspection readiness, ... Consultant. Throughout his career, Mr. Movahhed has helped design and manage oncology, neurology, ...
(Date:8/12/2020)... SEATTLE (PRWEB) , ... August 12, 2020 , ... ... tracking and monitoring systems that are ideal for public health agencies of all ... containing contagious diseases and helping at-risk individuals find appropriate health care, Mosio helps ...
Breaking Biology News(10 mins):
(Date:8/12/2020)... ... August 11, 2020 , ... ... is making available for free its new white paper – Simulated Transport ... testing into today’s biologics licensing application (BLA). In response, Modality Solutions shares ...
(Date:8/3/2020)... ... August 03, 2020 , ... ... Corrigan, President and CEO has been named one of the 100 most inspiring ... sectors, PharmaVoice 100 honorees are selected based on how they have inspired their ...
(Date:7/31/2020)... COLLEGE STATION, Texas (PRWEB) , ... July 29, ... ... pre-qualified cleanroom solutions today announced the launch of its new tagline, “BUILDING FOR ... within the biopharmaceutical industry and around the globe, requiring fast track capacity to ...
(Date:7/31/2020)... N.J (PRWEB) , ... July 29, 2020 , ... ... company, and Catalent, the leading global provider of advanced delivery technologies, development, and ... today announced that they have entered into a strategic partnership whereby Catalent will ...
Breaking Biology Technology:
Cached News: