DNA machine
Encyclopedia
A DNA machine is a molecular machine
constructed from DNA
. Research into DNA machines was pioneered in the late 1980s by Nadrian Seeman
and co-workers from New York University
. DNA is used because of the numerous biological tools already found in nature that can affect DNA, and the immense knowledge of how DNA works previously researched by biochemists
.
DNA machines can be logically designed since DNA assembly of the double helix is based on strict rules of base pairing that allow portions of the strand to be predictably connected based on their sequence. This 'selective stickiness' is a key advantage in the construction of DNA machines.
An example of a DNA machine was reported by Bernard Yurke and co-workers at Lucent Technologies
in the year 2000, who constructed molecular tweezers out of DNA.
The DNA tweezers contain three strands: A, B and C. Strand A latches onto half of strand B and half of strand C, and so it joins them all together. Strand A acts as a hinge so that the two 'arms' — AB and AC — can move. The structure floats with its arms open wide. They can be pulled shut by adding a fourth strand of DNA (D) 'programmed' to stick to both of the dangling, unpaired sections of strands B and C. The closing of the tweezers was proven by tagging strand A at either end with light-emitting molecules that do not emit light when they are close together. To re-open the tweezers add a further strand (E) with the right sequence to pair up with strand D. Once paired up, they have no connection to the machine BAC, so float away. The DNA machine can be opened and closed repeatedly by cycling between strands D and E. These tweezers can be used for removing drugs from inside fullerenes as well as from a self assembled DNA tetrahedron
. The state of the device can be determined by measuring the separation between donor and acceptor fluorophores using FRET.
Molecular machine
A molecular machine, or nanomachine, is any discrete number of molecular components that produce quasi-mechanical movements in response to specific stimuli . The expression is often more generally applied to molecules that simply mimic functions that occur at the macroscopic level...
constructed from DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
. Research into DNA machines was pioneered in the late 1980s by Nadrian Seeman
Nadrian Seeman
Nadrian C. "Ned" Seeman is an American nanotechnologist and crystallographer known for inventing the field of DNA nanotechnology.Seeman studied biochemistry at the University of Chicago and crystallography at the University of Pittsburgh...
and co-workers from New York University
New York University
New York University is a private, nonsectarian research university based in New York City. NYU's main campus is situated in the Greenwich Village section of Manhattan...
. DNA is used because of the numerous biological tools already found in nature that can affect DNA, and the immense knowledge of how DNA works previously researched by biochemists
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...
.
DNA machines can be logically designed since DNA assembly of the double helix is based on strict rules of base pairing that allow portions of the strand to be predictably connected based on their sequence. This 'selective stickiness' is a key advantage in the construction of DNA machines.
An example of a DNA machine was reported by Bernard Yurke and co-workers at Lucent Technologies
Lucent Technologies
Alcatel-Lucent USA, Inc., originally Lucent Technologies, Inc. is a French-owned technology company composed of what was formerly AT&T Technologies, which included Western Electric and Bell Labs...
in the year 2000, who constructed molecular tweezers out of DNA.
The DNA tweezers contain three strands: A, B and C. Strand A latches onto half of strand B and half of strand C, and so it joins them all together. Strand A acts as a hinge so that the two 'arms' — AB and AC — can move. The structure floats with its arms open wide. They can be pulled shut by adding a fourth strand of DNA (D) 'programmed' to stick to both of the dangling, unpaired sections of strands B and C. The closing of the tweezers was proven by tagging strand A at either end with light-emitting molecules that do not emit light when they are close together. To re-open the tweezers add a further strand (E) with the right sequence to pair up with strand D. Once paired up, they have no connection to the machine BAC, so float away. The DNA machine can be opened and closed repeatedly by cycling between strands D and E. These tweezers can be used for removing drugs from inside fullerenes as well as from a self assembled DNA tetrahedron
Tetrahedron
In geometry, a tetrahedron is a polyhedron composed of four triangular faces, three of which meet at each vertex. A regular tetrahedron is one in which the four triangles are regular, or "equilateral", and is one of the Platonic solids...
. The state of the device can be determined by measuring the separation between donor and acceptor fluorophores using FRET.