Enzymatic Synthesis of a DNA Triblock Copolymer that is Composed of Natural and Unnatural Nucleotides

Abstract

DNA molecules have come under the spotlight as potential templates for the fabrication of nanoscale products, such as molecular-scale electronic or photonic devices. Herein, we report an enhanced approach for the synthesis of oligoblock copolymer-type DNA by using the Klenow fragment exonuclease minus of E. coli DNA polymerase I (KF(-) ) in a multi-step reaction with natural and unnatural nucleotides. First, we confirmed the applicability of unnatural nucleotides with 7-deaza-nucleosides-which was expected because they were non-metalized nucleotides-on the unique polymerization process known as the "strand-slippage model". Because the length of the DNA sequence could be controlled by tuning the reaction time, analogous to a living polymerization reaction on this process, stepwise polymerization provided DNA block copolymers with natural and unnatural bases. AFM images showed that this DNA block copolymer could be metalized sequence-selectively. This approach could expand the utility of DNA as a template.

Mammary cell proliferation and catabolism of adipose tissues in nutrition-restricted lactating sows were associated with extracellular high glutamate levels

“…In this study, it was found that the expression of cell proliferation related genes ( CCND1 , CCND2 , CCND3 , CDK4 , CCNB1 , CDK1 , MKI67 ) in mammary glands was not different between the CON and RFA groups, suggesting the similar status of mammary cell proliferation between groups. In support of this notion, the expression of genes ( CAD , PPAT , PSAT1 , GOT1 , GOT2 ) encoding enzymes responsible for the synthesis of nucleotides, the basic materials for DNA synthesis [ 37 ], was also not different between the CON and RFA groups. Although most metabolites concentrations in mammary vein showed similar levels between groups, intriguingly, the RFA group had higher extracellular glutamate concentration than the CON group.…”

Fabrication of Metal Nanostructures on DNA Templates

“…The sequence-specific recognition properties and chemical reactivity of nucleic acids can be easily modulated by incorporating synthetic nucleotides endowed with custom functional groups. Ijiro’s group has prepared a triblock copolymer composed of poly­(dG)/poly­(dC) parts and a poly­(7z-dG)/poly­(dC) part with sequence-selective platinum metal deposition on the GC part of the DNA block copolymers. Braun and co-workers reported sequence-specific patterning of DNA metal coating using RecA protein that prevented Ag deposition by serving as a resist .…”

Programmed Assembly of DNA Templates by Silver Nanowires

“…Previously, sequence specific metallization of poly(dG-dC) DNA was used for grafting quantum sized nanoparticle between conducting nanowires by selective polymerization and post metallization of divalent AuNP-DNA conjugates. [39][40] Also, triblock DNA copolymers comprising middle unnatural nucleo- tides and peripheral poly(dG-dC) DNA was used for creating nanojunction between the conducting wires. Although selective deposition of metals on poly(dG-dC) DNA could be effectively used for programmed assembly of conducting materials, their utilization as a bridge to connect individual DO-based templates and post-metallization is a major requirement towards potential nanoelectronic applications.…”