DNA origami
In biochemistry and biophysics, DNA origami is the name given to the folding of DNA in order to create any two- and three-dimensional shapes on the nanoscale .
principle
In the process of scaffolded DNA origami developed by Paul Rothemund at the California Institute of Technology , a long single strand of mostly viral DNA, the scaffold strand, is used . With the help of many shorter single strands of DNA, the staple strands , each of which binds to two points of the scaffold strands , the scaffold strand is folded to approximate the desired shape. By connecting scaffolding strands with several short stitching strands, a three-dimensional structure is created.
The basis of the method is that, due to the base pairing, matching (reverse complementary) sequences of nucleotides hybridize with one another thanks to the specific bond between complementary bases , which can be used for self-assembly . A staple strand, for example, the two halves of which are complementary to two sections of the scaffold strand , connects with each of its halves to the respective section of the scaffold strand . To do this, the long DNA molecule has to fold, as both sections are now “ stapled ” together by the staple strand .
The base sequence of the viral DNA (of the scaffold strand ) is known. There are oligonucleotides (the staple strands designed) and synthesized the scaffold beach keep as sent into the desired shape. The virus DNA is usually folded line by line into a grid that approximates the shape. If scaffold strands are mixed and heated under suitable conditions with staple strands , the intended figures are formed without any external directing influence. For this reason, this method is called self-assembling . Various two-dimensional shapes, including maps, stars and smileys, as well as three-dimensional structures such as tetrahedra, have already been created.
The advantages of this method are its relative simplicity, high yield and low cost. Many possible applications have been suggested in the literature, including sleeves for drug delivery, positioning of nanoparticles, and making resolution rulers for light microscopy (so-called nanometer rulers ). DNA origami is used, among other things, to make DNA machines .
Since the base pairing has a relatively high binding energy and only dissolves at temperatures above 90 ° C, other intramolecular forces of attraction and repulsion such as base stacking are used for temporary connections (e.g. with moving parts of a DNA machine) Changes in temperature or by adding cations can be controlled.
history
The first use of DNA to create structures was described in 1991 by Nadrian C. Seeman , with the aim of creating a framework for attaching biomolecules at regular intervals in order to be able to better examine non-crystallizable biomolecules using X-ray structure analysis.
Individual evidence
- ^ Paul WK Rothemund: Folding DNA to create nanoscale shapes and patterns. In: Nature 440 (7082): 297-302. doi : 10.1038 / nature04586 . PMID 16541064 . (2006).
- ^ JJ Schmied, A. Gietl, P. Holzmeister, C. Forthmann, C. Steinhauer, T. Dammeyer, P. Tinnefeld: Fluorescence and super-resolution standards based on DNA origami. In: Nature methods. Volume 9, Number 12, December 2012, pp. 1133-1134, doi : 10.1038 / nmeth.2254 . PMID 23223165 .
- ↑ T. Gerling, KF Wagenbauer, AM Neuner, H. Dietz: Dynamic DNA devices and assemblies formed by shape-complementary, non-base pairing 3D components. In: Science. 347, 2015, p. 1446, doi : 10.1126 / science.aaa5372 .
- ^ JH Chen, NC Seeman: Synthesis from DNA of a molecule with the connectivity of a cube. In: Nature. Volume 350, Number 6319, April 1991, pp. 631-633, doi : 10.1038 / 350631a0 . PMID 2017259 .