Artificial cell membrane channels composed of DNA can be opened and locked with a key
Graphic shows the bilayer structure of a living cell membrane, composed of phospholipid. A phospholipid consists of a hydrophilic or water-loving head and hydrophobic or water-fearing tail. The hydrophobic tails are sandwiched between two layers of hydrophilic heads. At the center, a channel is shown, permitting the transport of biomolecules. The new study describes a process for creating artificial channels using segments of DNA that insert into cell membranes and allow the reversible transit of various cargo, including ions and proteins. Credit: Biodesign Institute at ASU

Living cells are engaged in a lively import-export business just as countries import a vast array of consumer goods across national borders. They have ports of entry that are embedded with transport channels. Proper functioning and survival can be achieved by regulating what kinds of cargo can pass through the borderlands.

A professor from Arizona State University, along with his colleagues and international partners, describe the design and construction of artificial Membrane channels, engineered using short segments of DNA. The DNA constructions behave much like natural cell channels or pores, with enhanced features unavailable in their naturally occurring counterparts.

One day, these innovative DNA nanochannels may be used in a variety of scientific applications, ranging from biosensing and drug delivery applications to the creation of artificial cell networks capable of autonomously, concentrating, capturing, and delivering tiny cargo.

Many biological pores and channels are reversibility gated to allow ion or molecule to pass through. We mimic nature's processes to engineer DNA nanopores that can be locked and unlocked.

ProfessorYan is the Director of the Biodesign Center for Molecular Design and Biomimetics. He is a professor at the school.

The current issue of the journal Nature Communications contains research findings.

All living cells have a unique biological structure. The term for the outer and inner layers of a membranes is called a phospholipid bilayer.

The inner and outer layers are similar to the walls of a room. The space between inner and outer surfaces is like a sea. The cell is semipermeable, allowing designated cargo entry or exit from the cell. The opening of the Panama Canal is an example of how such transport can occur when the cargo binding with another molecule alters the dynamics of the channel.

Semipermeable cell membranes are necessary for protecting sensitive ingredients within the cell from a hostile environment outside.

A technique known as DNA nanotechnology has been used to explore the possibility of creating a synthetically created channel. The idea is simple. The double strands of DNA are held together by the base pairs of the molecule's 4 nucleotides.

Synthetic construction of an array or 2 and 3D nanostructures can be done with base pairs of DNA. Once a structure has been carefully designed, usually with the aid of computer, the DNA segments can be mixed together and self-assembled into the desired form.

The challenge of creating a semipermeable channel has been vexing. Conventional techniques have failed to replicate the structure and capacities of nature-made membrane channels and synthetic DNA nanopores generally permit only one-way transport of cargo.

A new study describes an innovative method that allows researchers to design and build a synthetic channel that can transport larger cargo than natural channels can. The new method of building the channel structure by assembling the component DNA segments horizontally is different from previous efforts. The method allows for the construction of larger holes in thepores, which will allow the transport of more biomolecules.

The lock and key mechanism of the DNA design allows the channel to be opened and closed by means of a hinged lid. The keys consist of sequence-specific DNA strands that bind with the lid of the channel and open or close it.

In a series of experiments, the researchers demonstrate the ability of the DNA channel to successfully transport cargo of varying sizes, ranging from tiny dye molecule to folded protein structures, some larger than the pore dimensions of natural membrane channels.

The structures were visualized using atomic force microscopy and transmission electron microscopy to confirm that they conformed to the original design specifications.

The fluorescent dye molecule was used to verify that the DNA channels successfully pierced and inserted themselves through the cell's lipid bilayer. The transport operation was carried out within an hour of channel formation, which is a significant improvement over previous DNA nanopores, which typically take up to 8 hours to complete.

It is possible to study the rapid and complex folding and unfolding of proteins with the help of the DNA nanochannels. The channels could be used to exert control over biomolecules entering cells. The ability to design artificial, self-assembling transport channels is likely to lead to many other possible applications.

More information: Swarup Dey et al, A reversibly gated protein-transporting membrane channel made of DNA, Nature Communications (2022). DOI: 10.1038/s41467-022-28522-2 Journal information: Nature Communications Citation: Artificial cell membrane channels composed of DNA can be opened and locked with a key (2022, May 10) retrieved 11 May 2022 from https://phys.org/news/2022-05-artificial-cell-membrane-channels-dna.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.