Monovalent Cation Size and DNA Conformational Stability

Biochemistry ◽  
2011 ◽  
Vol 50 (15) ◽  
pp. 3084-3094 ◽  
Author(s):  
Earle Stellwagen ◽  
Joseph M. Muse ◽  
Nancy C. Stellwagen
Keyword(s):  
Conformational Stability ◽  
Monovalent Cation ◽  
Cation Size

scholarly journals Structural Characterization and Comparison of Monovalent Cation-Exchanged Zeolite-W

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3684
Author(s):  
Donghoon Seoung ◽  
Hyeonsu Kim ◽  
Pyosang Kim ◽  
Chihyun Song ◽  
Suhyeong Lee ◽  
...  
Keyword(s):  
Volume Expansion ◽  
Structural Changes ◽  
Monovalent Cation ◽  
Water Molecules ◽  
Channel Opening ◽  
Group A ◽  
Framework Species ◽  
Cation Size ◽  
Cell Volumes ◽  
Channel Unit

We report comparative structural changes of potassium-contained zeolite-W (K-MER, structural analogue of natural zeolite merlinoite) and monovalent extra-framework cation (EFC)-exchanged M-MERs (M = Li+, Na+, Ag+, and Rb+). High-resolution synchrotron X-ray powder diffraction study precisely determines that crystal symmetry of MERs is tetragonal (I4/mmm). Rietveld refinement results reveal that frameworks of all MERs are geometrically composed of disordered Al/Si tetrahedra, bridged by linkage oxygen atoms. We observe a structural relationship between a group of Li-, Na-, and Ag-MER and the group of K- and Rb-MER by EFC radius and position of M(1) site inside double 8-membered ring unit (d8r). In the former group, a-axes decrease reciprocally, c-axes gradually extend by EFC size, and M(1) cations are located at the middle of the d8r. In the latter group, a- and c-axes lengths become longer and shorter, respectively, than axes of the former group, and these axial changes come from middle-to-edge migration of M(1) cations inside the d8r channel. Unit cell volumes of the Na-, Ag-, and K-MER are ca. 2005 Å3, and the volume expansion in the MER series is limited by EFC size, the number of water molecules, and the distribution of extra-framework species inside the MER channel. EFC sites of M(1) and M(2) show disordered and ordered distribution in the former group, and all EFC sites change to disordered distribution after migration of the M(1) site in the latter group. The amount of water molecules and porosities are inversely proportional to EFC size due to the limitation of volume expansion of MERs. The channel opening area of a pau composite building unit and the amount of water molecules are universally related as a function of cation size because water molecules are mainly distributed inside a pau channel.

Influence of Monovalent Cation Size on Nanodomain Formation in Anionic–Zwitterionic Mixed Bilayers

2017 ◽  
Vol 121 (4) ◽  
pp. 787-799 ◽  
Author(s):  
Sai J. Ganesan ◽  
Hongcheng Xu ◽  
Silvina Matysiak
Keyword(s):  
Monovalent Cation ◽  
Cation Size

scholarly journals The Influence of Monovalent Cation Size on the Stability of RNA Tertiary Structures

2009 ◽  
Vol 390 (4) ◽  
pp. 791-804 ◽  
Author(s):  
Dominic Lambert ◽  
Desirae Leipply ◽  
Ross Shiman ◽  
David E. Draper
Keyword(s):  
Monovalent Cation ◽  
Tertiary Structures ◽  
The Stability ◽  
Cation Size

Insights into the Structural Features, Conformational Stability and Functional Activity of the Olneya tesota PF2 Lectin

2020 ◽  
Vol 27 ◽  
Author(s):  
Edgar Acedo-Espinoza ◽  
Irlanda Lagarda-Diaz ◽  
Rosina Cabrera ◽  
Ana M. Guzman-Partida ◽  
Amir Maldonado-Arce ◽  
...  
Keyword(s):  
Tertiary Structure ◽  
Proteolytic Enzymes ◽  
Conformational Stability ◽  
Structural Features ◽  
Beta Sheets ◽  
Hemagglutinating Activity ◽  
Effect Of Temperature ◽  
Hydrodynamic Diameter ◽  
Bioinformatic Tools ◽  
Structural Levels

Background: The O. tesota lectin PF2 is a tetrameric protein with subunits of 33 kDa that recognizes only complex carbohydrates, resistant to proteolytic enzymes and has insecticidal activity against Phaseolus beans pest. Objective: To explore PF2 lectin features at different protein structural levels and to evaluate the effect of temperature and pH on its functionality and conformational stability. Methods: PF2 lectin was purified by affinity chromatography. Its primary structure was resolved by mass spectrometry and analyzed by bioinformatic tools, including its tertiary structure homology modeling. The effect of temperature and pH on its conformational traits and stability was addressed by dynamic light scattering, circular dichroism, and intrinsic fluorescence. The hemagglutinating activity was evaluated using a suspension of peripheral blood erythrocytes. Results: The proposed PF2 folding comprises a high content of beta sheets. At pH 7 and 25 °C, the hydrodynamic diameter (Dh) was found to be 12.3 nm which corresponds to the oligomeric native state of PF2 lectin. Dh increased under the other evaluated pH and temperature conditions, suggesting protein aggregation. At basic pH, PF2 exhibited low conformational stability. The native PF2 (pH 7) retained its full hemagglutinating activity up to 45 °C and exhibited one transition state with a melting temperature of 76.8 °C. Conclusion: PF2 showed distinctive characteristics found in legume lectins. The pH influences the functionality and conformational stability of the protein. PF2 lectin displayed a relatively narrow thermostability to the loss of secondary structure and hemagglutinating activity.

Sign in / Sign up

Export Citation Format

Share Document