Understanding the role of base pairing and stacking displayed by polynucleotide chains interwind together resulting in a double-helical B-DNA type structure is crucial to gaining access to the sophisticated structural arrangement of DNA. Several computational and experimental studies hinted towards the dominance of base pairing over stacking for duplex stability. To find out how significant the individual Watson-Crick hydrogen bonds are in maintaining the double-helical integrity of the DNA, in the present article, we selectively switched off the hydrogen bonds (one specific bond or their combinations in all the base pairs at a time) via manipulating the force fields for A-T and G-C base pairs. We studied 12 systems in total via all-atom explicit-solvent molecular dynamics simulations (200 ns each). The MD output structures were compared with the control system by means of structural, dynamic, and energetic properties to monitor the overall consequences of removing H-bond(s) on the B-DNA characteristics of the model systems. Our findings suggest that all the individual hydrogen bonds involved in base pairing are vital for maintaining the DNA structural integrity as any possible alteration in Watson-Crick hydrogen bond(s) leads to the disintegration/collapse of DNA strands resulting in unfolded states.
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http://dx.doi.org/10.1016/j.bpc.2021.106758 | DOI Listing |
Dalton Trans
January 2025
Department of Inorganic Chemistry, Shahid Beheshti University, 1983969411, Tehran, Iran.
In a systematic study, six pseudopolymorphic coordination polymers containing the ditopic 1,3-di(pyridin-4-yl)urea ligand (4bpu) constructed with d metal cations, possessing the formula {[M(4bpu)I]S} [(M = Zn, Cd and Hg), (S = MeOH or EtOH)], namely Zn-MeOH, Zn-EtOH, Cd-MeOH, Cd-EtOH, Hg- and Hg-EtOH were obtained. The title compounds were characterized by single-crystal X-ray diffraction analysis (SC-XRD), elemental analysis (CHN), FT-IR spectroscopy, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). The diffraction studies show that these compounds are isostructural 1D zig-zag chain coordination polymers which is also confirmed using XPac 2.
View Article and Find Full Text PDFAcc Chem Res
January 2025
The Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States.
ConspectusIn the search for efficient and selective electrocatalysts capable of converting greenhouse gases to value-added products, enzymes found in naturally existing bacteria provide the basis for most approaches toward electrocatalyst design. Ni,Fe-carbon monoxide dehydrogenase (Ni,Fe-CODH) is one such enzyme, with a nickel-iron-sulfur cluster named the C-cluster, where CO binds and is converted to CO at high rates near the thermodynamic potential. In this Account, we divide the enzyme's catalytic contributions into three categories based on location and function.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry, University of Washington, Seattle, Washington 98185, USA.
We derive a new expression for the strength of a hydrogen bond (VHB) in terms of the elongation of the covalent bond of the donor fragment participating in the hydrogen bond (ΔrHB) and the intermolecular coordinates R (separation between the heavy atoms) and θ (deviation of the hydrogen bond from linearity). The expression includes components describing the covalent D-H bond of the hydrogen bond donor via a Morse potential, the Pauli repulsion, and electrostatic interactions between the constituent fragments using a linear expansion of their dipole moment and a quadratic expansion of their polarizability tensor. We fitted the parameters of the model using ab initio electronic structure results for six hydrogen bonded dimers, namely, NH3-NH3, H2O-H2O, HF-HF, H2O-NH3, HF-H2O, and HF-NH3, and validated its performance for extended parts of their potential energy surfaces, resulting in a mean absolute error ranging from 0.
View Article and Find Full Text PDFApurinic/Apyrimidinic (AP)-sites are common and highly mutagenic DNA lesions that can arise spontaneously or as intermediates during Base Excision Repair (BER). The enzyme apurinic/apyrimidinic endonuclease 1 (APE1) initiates repair of AP-sites by cleaving the DNA backbone at the AP-site via its endonuclease activity. Here, we investigated the functional role of the APE1 active site residue N174 that contacts the AP-site during catalysis.
View Article and Find Full Text PDFChem Sci
January 2025
School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Chemical Theory and Mechanism, Chongqing University Chongqing 401331 China
Atomically precise gold nanoclusters have shown great promise as model electrocatalysts in pivotal electrocatalytic processes such as the hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CORR). Although the influence of ligands on the electronic properties of these nanoclusters is well acknowledged, the ligand effects on their electrocatalytic performances have been rarely explored. Herein, using [Au(SR)] nanoclusters as a prototype model, we demonstrated the importance of ligand hydrophilicity hydrophobicity in modulating the interface dynamics and electrocatalytic performance.
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