scholarly journals A Single Molecule Kinetic and Thermodynamic Approach to Oligonucleotide Duplex Formation

2012 ◽  
Vol 102 (3) ◽  
pp. 276a
Author(s):  
Nicholas F. Dupuis ◽  
David J. Nesbitt
Keyword(s):  
Single Molecule ◽  
Thermodynamic Approach ◽  
Oligonucleotide Duplex ◽  
Duplex Formation

Spectral and cyclic voltammetric characterization of self-assembled monolayers on gold of pyrene end-labeled oligonucleotide duplexes

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1077-1084 ◽  
Author(s):  
R Scott Reese ◽  
Marye Anne Fox
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Surface Emission ◽  
Assembled Monolayers ◽  
Oligonucleotide Duplex ◽  
Self Assembled ◽  
Duplex Formation

Self-assembled monolayers of sulfur-terminated oligonucleotide duplexes were formed on flat gold surfaces, either by exposure of a self-assembled monolayer bearing one oligonucleotide strand to the complementary strand or by preformation of a oligonucleotide duplex that was then deposited on a fresh gold surface. Virtually identical spectral behavior was observed whether the duplex was produced before deposition or by in situ complementary association. With a duplex bearing an appropriate pyrene end-label, the resulting thin film was photoresponsive. Surface emission measurements show no evidence for pyrene aggregation on the modified surfaces. The polarity of the photocurrent, reflecting photoinduced electron transfer initiated by photoexcitation of pyrene, is opposite that expected from the oligonucleotide-mediated reduction of the appended pyrene excited state.Key words: oligonucleotide, self-assembled monolayer, duplex formation, photoelectrochemistry, surface emission.

scholarly journals Specific DNA duplex formation at an artificial lipid bilayer: fluorescence microscopy after Sybr Green I staining

2014 ◽  
Vol 10 ◽  
pp. 2307-2321 ◽  
Author(s):  
Emma Werz ◽  
Helmut Rosemeyer
Keyword(s):  
Lipid Bilayer ◽  
Single Molecule ◽  
Dna Sequences ◽  
Sybr Green ◽  
Sybr Green I ◽  
Racemic Mixture ◽  
Dna Duplexes ◽  
Target Dna ◽  
Single Molecule Fluorescence Spectroscopy ◽  
Duplex Formation

The article describes the immobilization of different probe oligonucleotides (4, 7, 10) carrying each a racemic mixture of 2,3-bis(hexadecyloxy)propan-1-ol (1a) at the 5’-terminus on a stable artificial lipid bilayer composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). The bilayer separates two compartments (cis/trans channel) of an optical transparent microfluidic sample carrier with perfusion capabilities. Injection of unlabeled target DNA sequences (6, 8, or 9), differing in sequence and length, leads in the case of complementarity to the formation of stable DNA duplexes at the bilayer surface. This could be verified by Sybr Green I double strand staining, followed by incubation periods and thorough perfusions, and was visualized by single molecule fluorescence spectroscopy and microscopy. The different bilayer-immobilized complexes consisting of various DNA duplexes and the fluorescent dye were studied with respect to the kinetics of their formation as well as to their stability against perfusion.

scholarly journals Dynamics of the DNA Duplex Formation Studied by Single Molecule Force Measurements

2004 ◽  
Vol 87 (5) ◽  
pp. 3388-3396 ◽  
Author(s):  
U. Bockelmann ◽  
P. Thomen ◽  
F. Heslot
Keyword(s):  
Single Molecule ◽  
Force Measurements ◽  
Dna Duplex ◽  
Duplex Formation

scholarly journals Single-Molecule Manipulation of the Duplex Formation and Dissociation at the G-Quadruplex/i-Motif Site in the DNA Nanostructure

ACS Nano ◽  
2015 ◽  
Vol 9 (10) ◽  
pp. 9922-9929 ◽  
Author(s):  
Masayuki Endo ◽  
Xiwen Xing ◽  
Xiang Zhou ◽  
Tomoko Emura ◽  
Kumi Hidaka ◽  
...  
Keyword(s):  
Single Molecule ◽  
Dna Nanostructure ◽  
G Quadruplex ◽  
Motif Site ◽  
Duplex Formation ◽  
Single Molecule Manipulation

scholarly journals Single-Molecule Kinetics Reveal Cation-Promoted DNA Duplex Formation Through Ordering of Single-Stranded Helices

2013 ◽  
Vol 105 (3) ◽  
pp. 756-766 ◽  
Author(s):  
Nicholas F. Dupuis ◽  
Erik D. Holmstrom ◽  
David J. Nesbitt
Keyword(s):  
Single Molecule ◽  
Dna Duplex ◽  
Duplex Formation

Stopped-flow kinetics of locked nucleic acid (LNA)–oligonucleotide duplex formation: studies of LNA–DNA and DNA–DNA interactions

2001 ◽  
Vol 354 (3) ◽  
pp. 481-484 ◽  
Author(s):  
Ulla CHRISTENSEN ◽  
Nana JACOBSEN ◽  
Vivek K. RAJWANSHI ◽  
Jesper WENGEL ◽  
Troels KOCH
Keyword(s):  
Nucleic Acid ◽  
Dissociation Constants ◽  
Locked Nucleic Acid ◽  
Stopped Flow ◽  
Complementary Dna ◽  
Conformationally Restricted ◽  
Dna And Rna ◽  
Melting Curves ◽  
Oligonucleotide Duplex ◽  
Duplex Formation

The locked nucleic acid (LNA) monomer is a conformationally restricted nucleotide analogue with an extra 2′-O,4′-C-methylene bridge added to the ribose ring. Oligonucleotides that contain LNA monomers have shown greatly enhanced thermal stability when hybridized to complementary DNA and RNA and are considered most promising candidates for efficient recognition of a given mixed sequence in a nucleic acid duplex and as an antisense molecule. Here the kinetics and thermodynamics of a series of oligonucleotide duplex formations of DNA–DNA and DNA–LNA octamers were studied using stopped-flow absorption measurements at 25°C and melting curves. The reactions of the DNA octamer 5′-CAGGAGCA-3′ with its complementary DNA octamer 5′-TGCTCCTG-3′, and with the LNA octamers 5′-TLGCTCCTG-3′ (LNA-1), 5′-TLGCTLCCTG-3′ (LNA-2) and 5′-TLGCTLCCTLG-3′(LNA-3), containing respectively one, two or three thymidine 2′-O,4′-C-methylene-(D-ribofuranosyl) nucleotide monomers, designated TL, were studied. In all cases were seen fast second-order association reactions with kobs = 2×107M-1˙s-1. At 25°C the dissociation constants of the duplexes obtained from melting curves were: DNA–DNA, 10nM; DNA–LNA-1, 20nM; DNA–LNA-2, 2nM; and DNA–LNA-3, 0.3nM; thus the greatly enhanced duplex stability induced by LNA is confirmed. Since the association rates were all equal this increase in stability is due to slower rates of dissociation of the complexes.

The method of replication affects metal film granularity and resolution

1989 ◽  
Vol 47 ◽  
pp. 708-709
Author(s):  
George C. Ruben
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Film Thickness ◽  
Single Molecule ◽  
Metal Film ◽  
Vertical Surface ◽  
High Resolution Imaging ◽  
Controllable Factors ◽  
Resolution Imaging

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.

Single molecule optical diffraction: A tool for understanding the structure of triple stranded left-hand helical cellulose

1989 ◽  
Vol 47 ◽  
pp. 1024-1025
Author(s):  
George C. Ruben ◽  
William Krakow
Keyword(s):  
Single Molecule ◽  
Helical Structure ◽  
Optical Diffraction ◽  
Maximum Diameter ◽  
Primary Cell Wall ◽  
Cellulose Synthesis ◽  
Left Hand ◽  
Left Handed ◽  
Freeze Dried ◽  
Diffraction Patterns

Tobacco primary cell wall and normal bacterial Acetobacter xylinum cellulose formation produced a 36.8±3Å triple-stranded left-hand helical microfibril in freeze-dried Pt-C replicas and in negatively stained preparations for TEM. As three submicrofibril strands exit the wall of Axylinum , they twist together to form a left-hand helical microfibril. This process is driven by the left-hand helical structure of the submicrofibril and by cellulose synthesis. That is, as the submicrofibril is elongating at the wall, it is also being left-hand twisted and twisted together with two other submicrofibrils. The submicrofibril appears to have the dimensions of a nine (l-4)-ß-D-glucan parallel chain crystalline unit whose long, 23Å, and short, 19Å, diagonals form major and minor left-handed axial surface ridges every 36Å.The computer generated optical diffraction of this model and its corresponding image have been compared. The submicrofibril model was used to construct a microfibril model. This model and corresponding microfibril images have also been optically diffracted and comparedIn this paper we compare two less complex microfibril models. The first model (Fig. 1a) is constructed with cylindrical submicrofibrils. The second model (Fig. 2a) is also constructed with three submicrofibrils but with a single 23 Å diagonal, projecting from a rounded cross section and left-hand helically twisted, with a 36Å repeat, similar to the original model (45°±10° crossover angle). The submicrofibrils cross the microfibril axis at roughly a 45°±10° angle, the same crossover angle observed in microflbril TEM images. These models were constructed so that the maximum diameter of the submicrofibrils was 23Å and the overall microfibril diameters were similar to Pt-C coated image diameters of ∼50Å and not the actual diameter of 36.5Å. The methods for computing optical diffraction patterns have been published before.

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