Effect of YOYO-1 on the mechanical properties of DNA

Soft Matter ◽  
2014 ◽  
Vol 10 (48) ◽  
pp. 9721-9728 ◽  
Author(s):  
Binu Kundukad ◽  
Jie Yan ◽  
Patrick S. Doyle

Atomic force microscopy studies show that binding of YOYO-1 to DNA increases the contour length of DNA without affecting the persistence length due to the underwinding of DNA.

2000 ◽  
Vol 39 (Part 1, No. 6B) ◽  
pp. 3711-3716 ◽  
Author(s):  
Hatsuki Shiga ◽  
Yukako Yamane ◽  
Etsuro Ito ◽  
Kazuhiro Abe ◽  
Kazushige Kawabata ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 687
Author(s):  
Amna Abdalla Mohammed Khalid ◽  
Pietro Parisse ◽  
Barbara Medagli ◽  
Silvia Onesti ◽  
Loredana Casalis

The MCM (minichromosome maintenance) protein complex forms an hexameric ring and has a key role in the replication machinery of Eukaryotes and Archaea, where it functions as the replicative helicase opening up the DNA double helix ahead of the polymerases. Here, we present a study of the interaction between DNA and the archaeal MCM complex from Methanothermobacter thermautotrophicus by means of atomic force microscopy (AFM) single molecule imaging. We first optimized the protocol (surface treatment and buffer conditions) to obtain AFM images of surface-equilibrated DNA molecules before and after the interaction with the protein complex. We discriminated between two modes of interaction, one in which the protein induces a sharp bend in the DNA, and one where there is no bending. We found that the presence of the MCM complex also affects the DNA contour length. A possible interpretation of the observed behavior is that in one case the hexameric ring encircles the dsDNA, while in the other the nucleic acid wraps on the outside of the ring, undergoing a change of direction. We confirmed this topographical assignment by testing two mutants, one affecting the N-terminal β-hairpins projecting towards the central channel, and thus preventing DNA loading, the other lacking an external subdomain and thus preventing wrapping. The statistical analysis of the distribution of the protein complexes between the two modes, together with the dissection of the changes of DNA contour length and binding angle upon interaction, for the wild type and the two mutants, is consistent with the hypothesis. We discuss the results in view of the various modes of nucleic acid interactions that have been proposed for both archaeal and eukaryotic MCM complexes.


Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 652
Author(s):  
Divine Sebastian ◽  
Chun-Wei Yao ◽  
Lutfun Nipa ◽  
Ian Lian ◽  
Gary Twu

In this work, a mechanically durable anticorrosion superhydrophobic coating is developed using a nanocomposite coating solution composed of silica nanoparticles and epoxy resin. The nanocomposite coating developed was tested for its superhydrophobic behavior using goniometry; surface morphology using scanning electron microscopy and atomic force microscopy; elemental composition using energy dispersive X-ray spectroscopy; corrosion resistance using atomic force microscopy; and potentiodynamic polarization measurements. The nanocomposite coating possesses hierarchical micro/nanostructures, according to the scanning electron microscopy images, and the presence of such structures was further confirmed by the atomic force microscopy images. The developed nanocomposite coating was found to be highly superhydrophobic as well as corrosion resistant, according to the results from static contact angle measurement and potentiodynamic polarization measurement, respectively. The abrasion resistance and mechanical durability of the nanocomposite coating were studied by abrasion tests, and the mechanical properties such as reduced modulus and Berkovich hardness were evaluated with the aid of nanoindentation tests.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1661
Author(s):  
Katarzyna Adamiak ◽  
Katarzyna Lewandowska ◽  
Alina Sionkowska

Collagen films are widely used as adhesives in medicine and cosmetology. However, its properties require modification. In this work, the influence of salicin on the properties of collagen solution and films was studied. Collagen was extracted from silver carp skin. The rheological properties of collagen solutions with and without salicin were characterized by steady shear tests. Thin collagen films were prepared by solvent evaporation. The structure of films was researched using infrared spectroscopy. The surface properties of films were investigated using Atomic Force Microscopy (AFM). Mechanical properties were measured as well. It was found that the addition of salicin modified the roughness of collagen films and their mechanical and rheological properties. The above-mentioned parameters are very important in potential applications of collagen films containing salicin.


2018 ◽  
Vol 114 (3) ◽  
pp. 513a
Author(s):  
Yuri M. Efremov ◽  
Mirian Velay-Lizancos ◽  
Daniel M. Suter ◽  
Pablo D. Zavattieri ◽  
Arvind Raman

PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e30204 ◽  
Author(s):  
David Martinez-Martin ◽  
Carolina Carrasco ◽  
Mercedes Hernando-Perez ◽  
Pedro J. de Pablo ◽  
Julio Gomez-Herrero ◽  
...  

Author(s):  
Hosam Gharib Abdelhady

Objectives: This research aims at investigating the effect of nano-encapsulating the MagnevistTM, a magnetic resonance imaging agent, within generation four, 1, 4- diaminobutane core polyamidoamine dendrimers on their molecular morphology and their nano-mechanical properties in liquid.Methods: Atomic force microscopy was applied in its imaging and force measuring modes to investigate, on the molecular scale, the morphological and nano-mechanical changes in generation four, 1, 4-diaminobutane core polyamidoamine dendrimers due to the nano-encapsulation of Magnevist in liquid.Results: The weight gain of dendrimers indicates the loading of ~ 30 Magnevist molecules. This has increased the rigidity of the dendrimer molecules, compared to unloaded dendrimers. Atomic force microscopy showed individual well-defined nano-spherical particles with nanoscopic dimensions of (40±13 nm in diameter and 4.38±0.54 nm in height). In contrast, imaging of non encapsulated dendrimers revealed loose aggregates of 15±3.5 nm in diameter and 0.9±0.2 nm in height.Conclusions: The atomic force microscopy, in liquid, was successfully applied to differentiate between Magnevist nano-encapsulated and non-encapsulated dendrimers, in their morphology and in their nano-mechanical properties. The results confirm the nano-encapsulation of Magnevist within generation four, 1,4-diaminobutane core polyamidoamine dendrimers. This loading increased the rigidity of the nanoencapsulated dendrimer, packed ~ 9 Magnevist-G 4 molecules together and may probably enhance the magnetic resonance images and increase their duration of time in the bloodstream when compared with Magnevist alone. Thus elongating the imaging sessions without the need for additional contrast agent doses.


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