Navigation Links
New technique reveals subtle force-induced changes in biomolecule's conformation
Date:10/16/2007

Scientists studying biological systems at the molecular level now have a new hybrid technique to probe the dynamics of the Holliday junction. The Holliday junction is a four-stranded DNA structure that forms during a process known as homologous recombination, which occurs when damaged DNA is repaired. Understanding how DNA repairs itself is an essential step in ultimately developing therapies for genetic disorders.

The hybrid technique is described by principal investigator Taekjip Ha and his colleagues at the University of Illinois in the Oct. 12 issue of Science. The Holliday junction is named after geneticist Robin Holliday, who proposed the model of DNA-strand exchange in 1964. To better understand the mechanisms and functions of proteins that interact with the Holliday junction, the researchers needed a way to study the structural and dynamic properties of the junction itself.

"Based on our previous studies, we knew the Holliday junction fluctuated between two structures, but how it moved from one place to the other and what intermediates were visited along the pathway were unknown," Ha said. With this latest work, the researchers have determined that the intermediate structure is similar to that of a Holliday junction bound to its own processing enzyme.

The hybrid technique combines the exquisite force control of an optical trap and the precise measurement capabilities of single-molecule fluorescence resonance energy transfer. To use the technique, researchers first attach two dye molecules--one green and one red--to the molecule they want to study. Next, they excite the green dye with a laser. Some of the energy moves from the green dye to the red dye, depending upon the distance between them. The changing ratio of the two intensities indicates the relative movement of the two dyes. Therefore, by monitoring the brightness of the two dyes, the researchers can determine the motion of the molecule. With the optical trap, a focused laser beam locks onto a microsphere attached to one end of the molecule to be studied. The optical trap can then pull on the molecule like a pair of tweezers.

The project is funded by the Physics and Molecular and Cellular Biosciences divisions at the National Science Foundation (NSF) through a CAREER award for the development and utilization of advanced single-molecule techniques to study the fundamentals of DNA-protein interactions.

Past techniques, such as X-ray crystallography and nuclear magnetic resonance, have provided a vast amount of structural detail for biological molecules, but the data is largely limited to a static view. Single molecule approaches make it possible to study dynamic interactions at the single molecule level. The ability to follow bioprocesses as they actually occur in real time transforms the way we visualize and ultimately understand the complex dynamics of living systems.

"The two NSF divisions supporting this project have been working closely together for several years to foster this research and other similar approaches," said NSF Program Manager Denise Caldwell. "These results highlight the importance of fostering a cross-disciplinary approach to understanding complex living systems because input from both directions is essential to the success of the project." She added that "a lot of junior scientists are migrating into fields like this one because the science is intellectually exciting."


'/>"/>

Contact: Diane Banegas
dbanegas@nsf.gov
703-292-4489
National Science Foundation
Source:Eurekalert

Related biology news :

1. New Technique for Tracking Gene Regulators
2. Live Recombinant Adenovirus Vaccine Technique Explored
3. New lab technique identifies high levels of pathogens in therapy pool
4. Brain-mapping technique aids understanding of sleep, wakefulness
5. Technique may allow cancer patients to freeze eggs, preserving fertility before starting treatment
6. Study reveals new technique for fingerprinting environmental samples
7. Researchers Find New Technique To Identify Fetal Genetic Material From Amniotic Fluid
8. Researchers pioneer new gene therapy technique using natural repair process
9. Newer imaging techniques may lead to over-treatment
10. Gene silencing technique offers new strategy for treating, curing disease
11. Mosaic mouse technique offers a powerful new tool to study diseases and genetics
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/2/2016)... MOUNTAIN VIEW, Calif. , Feb. 2, 2016 ... diabetic retinopathy market, Frost & Sullivan recognizes US-based ... North America Frost & Sullivan Award for New ... technology provider in North America ... standard in the rapidly growing diabetic retinopathy market. ...
(Date:1/28/2016)... SYNA ), a leading developer of human interface solutions, today ... --> --> Net revenue ... to the comparable quarter last year to $470.5 million. Net income ... $0.93 per diluted share. --> ... 2016 grew 9 percent over the prior year period to $60.3 ...
(Date:1/22/2016)... , January 22, 2016 /PRNewswire/ ... announced the addition of the  "Global ... their offering. --> http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ... the  "Global Behavioral Biometric Market 2016-2020" ... Research and Markets ( http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ) ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... ... February 11, 2016 , ... Reichert Technologies, which ... today to pursue the highest level of accuracy and quality with the addition ... and the AR5 Refractometer. Accurate, reliable and tough enough for the most ...
(Date:2/10/2016)... BioAmber Inc. (NYSE: BIOA ), a leader in ... Co. Ltd., its partner in the Sarnia ... additional CDN$25 million in the joint venture for 10% ... 40%.  Mitsui will also play a stronger role in ... Sarnia , providing dedicated resources alongside BioAmber,s commercial ...
(Date:2/10/2016)... , Feb. 10, 2016 NX Prenatal Inc., ... proprietary NeXosome® technology for early warning of adverse ... most recent study by Dr. Thomas McElrath ... Society for Maternal Fetal Medicine,s (SMFM) annual meeting held ... th , 2016.  The presentation reported initial positive ...
(Date:2/10/2016)... (NYSE MKT: ISR), a medical technology company and innovator ... treatment of prostate, brain, lung, head and neck and ... second quarter and six months of fiscal 2016, which ... --> Revenue was $1.19 million for ... 31, 2015, a 12% increase compared to $1.07 million ...
Breaking Biology Technology: