Researchers demonstrate continuous and controlled translocation of DNA polymer through a nanopore

Dec 02, 2010

Research published this week in JACS (Journal of the American Chemical Society) shows continuous and controlled translocation of a single stranded DNA (ssDNA) polymer through a protein nanopore by a DNA polymerase enzyme. The paper by researchers at the University of California Santa Cruz (UCSC) provides the foundation for a molecular motor, an essential component of Strand Sequencing using nanopores. Researchers at UCSC are collaborating with the UK-based company Oxford Nanopore Technologies, developers of a nanopore DNA sequencing technology.

The new research advances previous work showing that DNA could be moved through a nanopore using a polymerase. DNA movement in the previous study was performed by a series of polymerases and required complex electronics for control. Improvements noted in the JACS paper include techniques to allow continuous ssDNA movement, giving an uninterrupted signal as the strand was moved through the nanopore in real time. The enzyme-nanopore construct was active and measurable in a constant electronic field without complex electronics.

Controlled initiation of the polymerase processing at the site of the nanopore-enzyme complex allowed sequential measurement of multiple ssDNA molecules using a single experimental setup . Furthermore the polymerase exhibited tenacious binding with the DNA polymer, unlike previous enzymes researched in similar conditions. These results demonstrate that qualities of the phi29 DNA polymerase are commensurate with a strand sequencing technology.

In the 'strand sequencing' method of nanopore DNA sequencing, ionic current through a protein nanopore is measured and current disruptions used to identify bases on a ssDNA polymer in sequence, as it translocates the pore. Two key challenges for this method are: engineering a nanopore to enable identification of individual bases when a ssDNA spans the pore and a mechanism for controlling translocation of ssDNA at a consistent and appropriate speed to enable base identification through electronic measurements. Translocation techniques described in this paper are compatible with base identification technology being performed in the laboratories of Oxford Nanopore Technologies and its collaborators.

"This work with the phi29 polymerase has allowed us to make important progress on a key element of DNA strand sequencing," said investigator Professor Mark Akeson of the University of California, Santa Cruz. "While previous work showed that translocation control was possible in theory, this work shows that DNA translocation control is achievable in conditions that are compatible with an electronic sequencing technology. We look forward to further collaboration with Oxford Nanopore to realise this research."

"The 'strand sequencing' method of DNA sequencing using a nanopore has been studied for many years, but this paper shows for the first time that DNA can be translocated by an using methods that are consistent with a high throughput electronic technology," said Dr Gordon Sanghera, CEO of Oxford . "We are excited by this work and its potential when coupled with additional recent developments in DNA base identification on DNA strands, the other critical element for strand sequencing."

Explore further: Nanocontainers for nanocargo: Delivering genes and proteins for cellular imaging, genetic medicine and cancer therapy

More information: Processive Replication of Single DNA Molecules in a Nanopore Catalyzed by phi29 DNA Polymerase. Available online at pubs.acs.org/doi/abs/10.1021/ja1087612

Provided by Oxford Nanopore Technologies

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kevinrtrs
1 / 5 (4) Dec 02, 2010
It's quite clear from this article that the researchers needed zero input from [molecules-to-man] evolutionary theory. It is completely redundant and in fact a useless obstacle hiding in the corner, only necessary to be dusted off and used to obtain funding.

Just the fact that they required complex electronics in the beginning points out how difficult it was to obtain control of the first attempt to translocate the DNA molecule. Pores are there for a reason: absolute control and protection of the content of the nucleus. Without such protection any random event could destroy valuable parts of the cell.
This is what evolutionists don't want to hear - that the whole setup of the DNA molecule - from the chiral arrangements and high activation energy bond requirements - all of it has to do with protection of the biological from random physical events which might otherwise mimic the biological process results.
The whole arrangement PROTECTS against random mutational changes.Stops Evo dead.
Ethelred
not rated yet Dec 04, 2010
This is what evolutionists don't want to hear - that the whole setup of the DNA molecule - from the chiral arrangements and high activation energy bond requirements - all of it has to do with protection of the biological from random physical events which might otherwise mimic the biological process results.
I am curious. Why do you think rationalists wouldn't want to the hear the truth? All those things you mention can evolve and you do overstate them a bit as mutations do occur not only from copying errors but also from environmental factors.

The whole arrangement PROTECTS against random mutational changes
Which would be support for your position except that it is a false statement in that the protection is in now way complete. Mutations DO occur.
.Stops Evo dead.
Only mutation do happen thus evolution MUST occur.

Do you want to tell us how the Egyptians dealt with the Flood?

See I answer questions but you refuse to deal with hard questions.

Ethelred