Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanotechnology: Probing for interactions

29.11.2011
Nanoparticles offer insights into interactions between single-stranded DNA and their binding proteins

Double-stranded DNA must disentangle itself into single strands during replication or repair to allow functional molecules to bind and perform their various operations. Cellular proteins specifically bind to single-stranded DNA to prevent their premature recombination.

Unfortunately, detailed studies of these DNA–protein interactions have been hindered by the need for expensive instrumentation and time-consuming labelling techniques. Yen Nee Tan at the A*STAR Institute of Materials Research and Engineering and co-workers1 have now developed a convenient method to characterize the interactions between single-stranded DNA and their binding proteins.

The researchers used the optical properties of gold nanoparticles to probe the mechanism of protein–DNA binding. When the nanoparticles were well dispersed in solution, they yielded a bright red color, but when aggregated, the solution changed to blue. Tan and co-workers discovered that when single-stranded DNA and its binding protein were both present in the solution, coupled with a salt that stimulates nanoparticle aggregation, the DNA remained red in color, indicating that the DNA–protein complexes had bound with the nanoparticles through electrosteric stabilization forces. In contrast, when the protein or single-stranded DNA was introduced alone in the salt solution, there was a greater shift to the blue-grey color, indicating nanoparticle aggregation (see image).

“The greatest challenge in this work was to determine the optimum conditions for single-stranded DNA to bind with its binding protein to form complexes that confer the highest stability to gold nanoparticles from salt-induced aggregation,” says Tan.

The researchers attribute binding of the nanoparticles and the DNA–protein complexes to the presence of sulphur-containing groups in the protein, which are known to create strong bonds with gold. The protein molecules alone are smaller in molecular size than the protein–DNA complexes, leading to a less effective steric stabilization of the nanoparticles.

Tan and co-workers showed that there was a minimum length of DNA sequence under which the binding protein–DNA adhesion mechanism could operate. They found that the binding protein had a preference for binding to specific chemical units (bases) which make up DNA, and were able to spot DNA sequence variations, called single nucleotide polymorphisms (SNPs), even at the extreme ends of the molecule which are difficult to identify. Double-stranded DNA with SNPs cannot bind together so closely. The binding protein can thus attach to the dissociated single-stranded DNA to form protein–DNA complexes, offering sites to which gold nanoparticles can adhere.

“We plan to further develop this assay into a hassle-free genotyping assay to detect SNPs in real biological samples containing long genomic DNA,” says Tan.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering

Lee Swee Heng | Research asia research news
Further information:
http://www.a-star.edu.sg/
http://www.researchsea.com

More articles from Life Sciences:

nachricht For a chimpanzee, one good turn deserves another
27.06.2017 | Max-Planck-Institut für Mathematik in den Naturwissenschaften (MPIMIS)

nachricht New method to rapidly map the 'social networks' of proteins
27.06.2017 | Salk Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Extensive Funding for Research on Chromatin, Adrenal Gland, and Cancer Therapy

28.06.2017 | Awards Funding

Predicting eruptions using satellites and math

28.06.2017 | Earth Sciences

Extremely fine measurements of motion in orbiting supermassive black holes

28.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>