Visible light to control a reaction, has a number of advantages over other external stimuli: Light does not introduce contaminants into the reaction system, Excitation wavelength can be controlled through the design of the photo-responsive molecule, and It is now straightforward to control irradiation time and/or local excitation.
Figure 1: PHoto-regulation of tHe formation and dissoCiation of dna duPlexes witH azobenzene labeled oligonuCleotides reversible, and the azobenzene group does not decompose or induce undesirable side reactions even on repeated trans-cis isomerization. By introducing azobenzenes into DNA through D-threoninol as a linker, Asanuma and co-workers succeeded in achieving photo-regulation of: Formation and dissociation of a DNA duplex8,9 and Transcription by T7-RNA polymerase reaction10,11,12.
Photo-reGulation oF dna hyBridization For photo-regulation of DNA hybridization or DNA transcription as effected by T7-RNA polymerase, the azobenzene [X] residues must be inserted between the base pairs of the template DNA duplex. In other words, the X residue is introduced as a bulge adduct. For example, to make the sequence 5′-GCGAGTCG-3′ photo-responsive, the X residue must be incorporated in the sequence, without any base replacement to obtain 5′-GCGAXGTCG-3′. This sequence’s complementary strand, 3′-CGCTCAGC-5′, remains composed only of natural nucleotides. As long as the X residue is additionally inserted, there are no limitations with regard to the position of its introduction. X can equally be inserted at the center of a sequence or in the vicinity of its 5′- or 3′-terminus. The introduction of several X residues increases the DTm created by the photoinduced isomerization. For example, with the sequence described in the previous
When a photo-responsive molecule is directly attached to DNA as a receptor, photo-regulation of the bioprocess regulated by that DNA molecule could, in principle, be achieved. Such photo-responsive DNA could also be used as a switch in a DNA-based nano-machine. Professor Hiroyuki Asanuma and his group at the department of Molecular Design and Engineering of the Graduate School of Engineering of the Nagoya University (Japan) have developed an efficient method to achieve this goal. They have attached azobenzene to DNA and made it photo-responsive6,7. Azobenzene is a typical photo-responsive molecule that isomerizes from its planar trans-form to the non-planar cis-form after UV-light irradiation with a wavelength between 300 nm and 400 nm (lmax is around 330 nm). Interestingly, the system reverts from the cis-form to the trans-form after further irradiation with visible light (wavelength over 400 nm).1221186-53-3 Biological Activity This process is completely 8
paragraph with one X residue in the middle, the DTm between the trans [more stable] form and the cis form is 14.1454682-72-4 site 3 oC and with 2 residues as in 5′-G CXG AGT XCG-3′ the DTm between cis and trans is 21.PMID:20301544 5 oC. In order to photo-regulate the hybridization of relatively long duplexes efficiently, introduction of multiple azobenzenes is recommended. In this case as well, X residues should be additionally introduced without replacing any bases. A photo-responsive DNA sequence is designed as 5′-(NNX)n-NN-3′. If chemical modification is allowed to both strands, azobenzenes can be symmetrically introduced to both strands (i.e., 5′-(NNX)n-NN-3’/3′-(NXNnXN-5′) to further raise the photoregulatory efficiency13. Photo-sWitchinG oF t7 rna PolyMerase transcriPtion This application was describe.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
