Navigation Links
JILA finds flaw in model describing DNA elasticity
Date:9/14/2007

DNA, the biomolecule that provides the blueprint for life, has a lesser-known identity as a stretchy polymer. JILA scientists have found a flaw in the most common model for DNA elasticity, a discovery that will improve the accuracy of single-molecule research and perhaps pave the way for DNA to become an official standard for measuring picoscale forces, a notoriously difficult challenge. JILA is a joint venture of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder.

The JILA experiments, described in a new paper,* reveal that a classic model for measuring the elasticity of double-stranded DNA leads to errors when the molecules are short. For instance, measurements are off by up to 18 percent for molecules 632 nanometers long, and by 10 percent for molecules about twice that length. (By contrast, the DNA in a single human cell, if linked together and stretched out, would be about 2 meters long.)

The old elasticity model assumes that polymers are infinitely long, whereas the most popular length for high precision single-molecule studies is 600 nm to 2 microns, NIST/JILA biophysicist Tom Perkins says. Accordingly, several university collaborators developed a new theory, the finite worm-like chain (FWLC) model, which improves accuracy by incorporating three previously neglected effects, including length.

The work builds on JILA expertise in measuring positions of microscopic objects. A DNA molecule (green in the animation) is linked at one end to a moveable stage and at the other end to a polystyrene bead trapped by an infrared laser. While moving the stage to extend the DNA molecule, scientists measure changes in bead position using custom electronics and a second laser. By calculating the force exerted on the bead, based in part on the intensity of the laser, and comparing it to the position of the bead in the optical trap, which acts like a spring, scientists can measure DNA elasticity.

The JILA work is part of a NIST project studying possible use of DNA as a picoforce standard, because enzymes build DNA with atomic precision. DNA already is used informally to calibrate atomic force microscopes. An official standard could, for the first time, enable picoscale measurements that are traceable to internationally accepted units. DNA elasticity could provide a force standard from 0.1 -10 pico-Newtons (pN), where 1 pN is the approximate weight of 100 E. coli bacteria cells, and roughly 6 pN is the force exerted by 1 milliwatt of light reflected off a mirror.


'/>"/>

Contact: Laura Ost
laura.ost@nist.gov
303-497-4880
National Institute of Standards and Technology (NIST)
Source:Eurekalert

Related biology news :

1. Current human embryonic stem cell lines contaminated UCSD/Salk team finds
2. Another Look Finds Promising Proteomics Test is Not Biologically Plausible
3. Study finds more than one-third of human genome regulated by RNA
4. ASU researchers finds novel chemistry at work to provide parrots vibrant red colors
5. Same mutation aided evolution in many fish species, Stanford study finds
6. NC State scientist finds soft tissue in T. rex bones
7. New Treatment Rivals Chemotherapy For Lymphoma, Study Finds
8. Genrate: a generative model that finds and scores new genes and exons in genomic microarray data
9. Genetically modified rice in China benefits farmers health, study finds
10. Survey finds silver contamination in North Pacific waters
11. Anti cancer virotherapy well tolerated in first human administration, research finds
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:12/8/2016)... , Dec. 8, 2016 Market Research Future published a ... The global Mobile Biometric Security and Service Market is expected to ... 2022. Market Highlights: ... , Mobile Biometric Security ... to the increasing need of authentication and security from unwanted cyber ...
(Date:12/8/2016)... , Dec. 8, 2016  Singulex, Inc., the leader ... technology, entered into a license and supply agreement with ... The agreement provides Singulex access to Thermo Scientific BRAHMS ... is used to diagnose systemic bacterial infection ... to aid in assessing the risk of ...
(Date:12/7/2016)... India , December 7, 2016 According to a ... Machine Learning), Software Tool (Facial Expression, Voice Recognition), Service, Application Area, End User, ... is estimated to grow from USD 6.72 Billion in 2016 to USD 36.07 ... Continue Reading ... ...
Breaking Biology News(10 mins):
(Date:12/8/2016)... , Dec. 8, 2016 This report analyzes the ... Segments: Acid Based (Humic, Amino, & Fulvic), Extract Based, and ... following Crop Types: Ornamental & Turf, Row Crops, and Others. ... Canada , Japan , ... Latin America , and Rest of World. Annual ...
(Date:12/8/2016)... -- AskLinkerReports.com has published a report on Amyloglucosidase ... 2016 Market Research Report. From a basic outline of the ... all covered in the report. This report projects investment feasibility ... the Amyloglucosidase industry. ... , Complete report ...
(Date:12/8/2016)... ... December 08, 2016 , ... ... control cells — optogenetics — is key to exciting advances in the study ... spatially patterned light projected via free-space optics stimulates small, transparent organisms and excites ...
(Date:12/8/2016)... -- Anaconda BioMed S.L., a pre-clinical stage medical device company ... system for the treatment of Acute Ischemic Stroke (AIS), ... join its Scientific Advisory Board (SAB). The SAB is ... and clinical experts to Anaconda BioMed S.L., as the ... to its clinical phase. The SAB is also ...
Breaking Biology Technology: