Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Nanotechnology: Probing for interactions

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:

More articles from Life Sciences:

nachricht Molecular doorstop could be key to new tuberculosis drugs
20.03.2018 | Rockefeller University

nachricht Modified biomaterials self-assemble on temperature cues
20.03.2018 | Duke University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Thawing permafrost produces more methane than expected

20.03.2018 | Earth Sciences

Scientists invented method of catching bacteria with 'photonic hook'

20.03.2018 | Physics and Astronomy

Next Generation Cryptography

20.03.2018 | Information Technology

Science & Research
Overview of more VideoLinks >>>