Yuxiang Bu

Shandong University, Chi-nan-shih, Shandong Sheng, China

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Publications (179)411.36 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Density functional theory calculations suggest that β-turn peptide segments can act as a novel dual-relay elements to facilitate long-range charge hopping transport in proteins, with the N terminus relaying electron hopping transfer and the C terminus relaying hole hopping migration. The electron- or hole-binding ability of such a β-turn is subject to the conformations of oligopeptides and lengths of its linking strands. On the one hand, strand extension at the C-terminal end of a β-turn considerably enhances the electron-binding of the β-turn N terminus, due to its unique electropositivity in the macro-dipole, but does not enhance hole-forming of the β-turn C terminus because of competition from other sites within the β-strand. On the other hand, strand extension at the N terminal end of the β-turn greatly enhances hole-binding of the β-turn C terminus, due to its distinct electronegativity in the macro-dipole, but does not considerably enhance electron-binding ability of the N terminus because of the shared responsibility of other sites in the β-strand. Thus, in the β-hairpin structures, electron- or hole-binding abilities of both termini of the β-turn motif degenerate compared with those of the two hook structures, due to the decreased macro-dipole polarity caused by the extending the two terminal strands. In general, the high polarity of a macro-dipole always plays a principal role in determining charge-relay properties through modifying the components and energies of the highest occupied and lowest unoccupied molecular orbitals of the β-turn motif, whereas local dipoles with low polarity only play a cooperative assisting role. Further exploration is needed to identify other factors that influence relay properties in these protein motifs.
    ChemPhysChem 11/2014; · 3.35 Impact Factor
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    ABSTRACT: We present an ab initio molecular dynamics simulation study of a CH3CN-(H2O)40 cluster with an excess electron (EE) injected vertically in this work. Instead of surface bound or internally solvated electron, a hydrated CH3CN- is firstly formed as the CN transient after geometrical relaxation. The driving forces for the formation of CH3CN- are bending vibration of <CCN angle which initiates transfer of an extra charge to the CH3CN LUMO and hydration effect of the immediate water molecules which plays a stabilizing role. Solvent thermal fluctuation can lead to different resonances (the quasi-C2-resonance versus quasi-N-resonance) from the CN transient and further cause the hydrated CH3CN- system to evolve via two distinctly different pathways featuring spontaneous proton transfer to the central C and N sites, producing two different protonation products, respectively. The solvent thermal fluctuation induced formation of hydrogen bonding with the corresponding sites (C2 versus N) are responsible for the quasi-resonances and interconversion between three resonant structures and further proton transfers featuring spontaneous transfer of a proton to C2 or to N from its a interacting water molecule. The duration of CH3CN- for either of the two proton transfer processes is less than 200 fs. On the basis of experimental ESR results in which only the CH3CHN radical was found and present theoretical calculations, it is suggested that the trans-CH3CNH radical can be further converted to the CH3CHN radical via a water-mediated hydrogen atom transfer path.
    The Journal of Physical Chemistry A 05/2014; · 2.77 Impact Factor
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    ABSTRACT: Due to the fact that natural DNA may lack sufficient conductance for direct application in molecular electronics, a novel design of outer-expanded purine analogues was proposed by incorporating an aromatic ring at the N7-C8 site into natural G and A bases from the outside. The effect of the outer-expansion modification on electronic properties of DNA was investigated by density functional theory and molecular dynamics. The analyses revealed that these purine analogues not only preserve the same sizes of natural purine bases, thus avoiding distortions of DNA skeleton induced by the normal ring-inner-expansion modification, but also keep the selectivity of pairing with their natural counterpart C and T bases. More importantly, their electronic properties are enhanced, indicated by the narrowed HOMO–LUMO gaps, the lowered ionization potentials and the improved ultraviolet absorption spectra. This work may provide helpful information for designing of artificial bases as promising building blocks of biomolecular nanowires. © 2014 Wiley Periodicals, Inc.
    International Journal of Quantum Chemistry 04/2014; · 1.17 Impact Factor
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    ABSTRACT: Unrestricted density functional theory calculations in combination with the broken symmetry approach have been employed to study several benzylic carbanions. As a free anion, 2-(3,5-dinitrophenyl)-1,3-dithiane carbanion has near-degenerate singlet and triplet states and appears to be a promising magnetism-tunable species. In this work, we computationally design some of its derivatives in two ways: expanding the π-conjugated structures and introducing Lewis acids (Li+, Na+, and K+, and polar molecules are considered here) with different acidities. Calculations reveal that ring expansion does not change its open-shell broken symmetry singlet diradical ground state and antiferromagnetic character, but decreases its magnetism, whereas introduction of Lewis acids can lead to different ground states (triplet vs. singlet) and different magnetism, depending on the binding sites of the Lewis acid. That is, they show closed-shell singlet ground states without magnetism when a cation locates near the anionic center of the 1,3-dithiane ring, but convert to triplet as their ground states with ferromagnetic character when the cation moves to one nitro group of the 3,5-dinitrophenyl-based π-conjugation-expanded fragment. These findings regarding modulation through ring expansion and Lewis acid-binding ways make the magnetisms of 2-(3,5-dinitrophenyl)-1,3-dithiane-based carbanions tunable, and thus provide prospects of a new extension of the results from the previous study for designing magnetism-tunable building blocks for novel electromagnetic materials.
    Theoretical Chemistry Accounts 04/2014; 133(4). · 2.14 Impact Factor
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    ABSTRACT: The proton/electron transfer reactions between cysteine residue (Cys) and tyrosinyl radical (Tyr(•)) are an important step for many enzyme-catalyzed processes. Based on the statistical analysis of protein data bank, we designed three representative models to explore the possible proton/electron transfer mechanisms from Cys to Tyr(•) in proteins. Our ab initio calculations on simplified models and quantum mechanical/molecular mechanical (QM/MM) calculations on real protein environment reveal that the direct electron transfer between Cys and Tyr(•) is difficult to occur, but an inserted water molecule can greatly promote the proton/electron transfer reactions by a double-proton-coupled electron transfer (dPCET) mechanism. The inserted H2O plays two assistant roles in these reactions. The first one is to bridge the side chains of Tyr(•) and Cys via two hydrogen bonds which acts as the proton pathway, and the other one is to enhance the electron overlap between the lone-pair orbital of sulphur atom and the π-orbital of phenol moiety, and to function as electron transfer pathway. This water-mediated dPCET mechanism may offer great help for us to understand the detailed electron transfer processes between Tyr and Cys residues in proteins, such as the electron transfer from Cys439 to Tyr730(•) in the class I ribonucleotide reductase.
    Journal of the American Chemical Society 03/2014; · 10.68 Impact Factor
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    ABSTRACT: In this article we present density functional theory (DFT) calculations on the iron(IV)-oxo catalyzed methane C-H activation reactions for complexes in which the FeIV=O core is surrounded by five negatively charged ligands. We found that it follows a hybrid pathway that mixes features of the classical σ and π pathways in quintet surfaces. These calculations show that, the Fe-O-H arrangement in this hybrid pathway is bent, in sharp contrast to the collinear character as observed for the classical quintet σ pathways before. The calculations have also shown that it is the equatorial ligands that play key roles in tuning the reactivity of FeIV=O complexes. The strong π-donating equatorial ligands employed in the current study cause a weak π(FeO) bond and thereby shift the electronic accepting orbitals (EAO) from the vertically orientated O pz orbital to the horizontally orientated O px. In addition, all the equatorial ligands are small in size and would therefore be expected have small steric effects upon substrate horizontal approaching. Therefore, for the small and strong π-donating equatorial ligands, the collinear Fe-O-H arrangement is not the best choice for the quintet reactivity. This study adds new element to iron(IV)-oxo catalyzed C-H bond activation reactions.
    The Journal of Physical Chemistry B 01/2014; · 3.61 Impact Factor
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    ABSTRACT: In view of the important implications of excess electrons (EEs) interacting with CO2-H2O clusters in many fields, using ab initio molecular dynamics simulation technique, we reveal the structures and dynamics of an EE associated with its localization and subsequent time evolution in heterogeneous CO2-H2O mixed media. Our results indicate that although hydration can increase the electron-binding ability of a CO2 molecule, it only plays an assisting role. Instead, it is the bending vibrations that play the major role in localizing the EE. Due to enhanced attraction of CO2, an EE can stably reside in the empty, low-lying π* orbital of a CO2 molecule via a localization process arising from its initial binding state. The localization is completed within a few tens of femtoseconds. After EE trapping, the ∠OCO angle of the core CO2- oscillates in the range of 127°̃142°, with an oscillation period of about 48 fs. The corresponding vertical detachment energy of the EE is about 4.0 eV, which indicates extreme stability of such a CO2-bound solvated EE in [CO2(H2O)n]- systems. Interestingly, hydration occurs not only on the O atoms of the core CO2- through formation of O⋯H-O H-bond(s), but also on the C atom, through formation of a C⋯H-O H-bond. In the latter binding mode, the EE cloud exhibits considerable penetration to the solvent water molecules, and its IR characteristic peak is relatively red-shifted compared with the former. Hydration on the C site can increase the EE distribution at the C atom and thus reduce the C⋯H distance in the C⋯H-O H-bonds, and vice versa. The number of water molecules associated with the CO2- anion in the first hydration shell is about 4̃7. No dimer-core (C2O4-) and core-switching were observed in the double CO2 aqueous media. This work provides molecular dynamics insights into the localization and time evolution dynamics of an EE in heterogeneous CO2-H2O media.
    12/2013; 140(4).
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    ABSTRACT: We report an ab initio molecular dynamics simulation study of the solvation and dynamics of an excess electron in liquid acetonitrile (ACN). Four families of states are observed: a diffusely solvated state and three ACN core-localized states with monomer core, quasi-dimer (π*-Rydberg mode) core, and dual-core/dimer core (a coupled dual-core). These core localized states cannot be simply described as the corresponding anions because only a part of the excess electron resides in the core molecule(s). The quasi-dimer core state actually is a mixture that features cooperative excess electron capture by the π* and Rydberg orbitals of two ACNs. Well-defined dimer anion and solvated electron cavity were not observed in the 5–10 ps simulations, which may be attributed to slow dynamics of the formation of the dimer anion and difficulty of the formation of a cavity in such a fluxional medium. All of the above observed states have near-IR absorptions and thus can be regarded as the solvated electron states but with different structures, which can interpret the experimentally observed IR band. These states undergo continuous conversions via a combination of long-lasting breathing oscillation and core switching, characterized by highly cooperative oscillations of the electron cloud volume and vertical detachment energy. The quasi-dimer core and diffusely solvated states dominate the time evolution, with the monomer core and dual-core/dimer core states occurring occasionally during the breathing and core switching processes, respectively. All these oscillations and core switchings are governed by a combination of the electron-impacted bending vibration of the core ACN molecule(s) and thermal fluctuations.
    Journal of Chemical Theory and Computation 10/2013; 9(11):4727–4734. · 5.39 Impact Factor
  • Mei Wang, Jing Zhao, Yuxiang Bu
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    ABSTRACT: We present a computational study of the double-electron oxidized guanine-cytosine base pair as well as its deprotonated derivatives, focusing on their structural and electronic properties. Some novel electromagnetic characteristics are found. A hydrazine-like (N-N) cross-linked structure between the G and C radical moieties is the lowest-energy one for the [GC](2+) complexes. Double-electron oxidation can considerably destabilize the GC unit and leads to a barrier-hindered dissociation channel with negative dissociation energy. This channel is governed by a balance between electrostatic repulsion and attractive hydrogen-bonding interaction co-existing between G˙(+) and C˙(+). The proton/electron transfer reactions in the double-electron oxidized Watson-Crick base pair occur through a proton transfer induced charge migration mechanism. For the deprotonated [GC](2+) derivative, the [G(-H(+))C](+) series prefers to accompany by transfer of an electron from the G to C moiety when the G(+) is deprotonated, and its highest-doubly occupied molecular orbital mainly localizes over the C moiety with a π-bonding character. For the diradical G˙(+)C(-H)˙ series in which the C moiety is deprotonated, the two unpaired electrons reside one on each moiety in the π system. The diradical base pairs possess open-shell broken symmetry singlet states, and their magnetic coupling interactions are controlled by both intra- and inter-molecular interactions. The double-electron oxidized Watson-Crick base pair shows strong antiferromagnetic coupling, whereas the magnetic interactions of other diradical derivatives are relatively weak. This study highlights the crucial role of H-bonding in determining the magnetic interactions.
    Physical Chemistry Chemical Physics 09/2013; · 4.20 Impact Factor
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    ABSTRACT: We present here a theoretical investigation of the structural and electronic properties of the di-ionized GG base pairs (G•+G•+,G(-H1)•G•+, and G(-H1)•G(-H1)•)consisting of the guanine cation radical (G•+) and/or dehydrogenated guanine radical (G(-H1)•) using density functional theory calculations. Different coupling modes (Watson-Crick/WC, Hoogsteen/Hoog, and minor groove/min hydrogen bonding, and - stacking modes) are considered. We infer that a series of G•+G•+ complexes can be formed by the high-energy radiation. On the basis of density functional theory and complete active space self-consistent (CASSCF) calculations, we reveal that in the H-bonded and N-N cross-linked modes, (G•+G•+)WC, (G(-H1)•G•+)minII, (G(-H1)•G•+)minIII, (G(-H1)•G(-H1)•)WC, (G(-H1)•G(-H1)•)minI, and (G(-H1)•G(-H1)•)minIII have the triplet ground states, (G•+G•+)HoogI, (G(-H1)•G•+)WC, (G(-H1)•G•+)HoogI, (G(-H1)•G•+)minI, and (G(-H1)•G(-H1)•)minII possess open-shell broken-symmetry diradical-characterized singlet ground states, and (G•+G•+)HoogII, (G•+G•+)minI, (G•+G•+)minII, (G•+G•+)minIII, (G•+G•+)HoHo, (G(-H1)•G•+)HoHo, and (G(-H1)•G(-H1)•)HoHo are the closed-shell systems. For these H-bonded diradical complexes, the magnetic interactions are weak, especially in the diradical G•+G•+ series and G(-H1)•G(-H1)• series. The magnetic coupling interactions of the diradical systems are controlled by intermolecular interactions (H-bond, electrostatic repulsion, and radical coupling). The radical-radical interaction in the π-π stacked di-ionized GG base pairs ((G•+G•+)ππ, (G(-H1)•G•+)ππ, and (G(-H1)•G(-H1)•)ππ) are also considered, and the magnetic coupling interactions in these π-π stacked base pairs are large. This is the first theoretical prediction that some di-ionized GG base pairs possess diradical characters with variable degrees of ferromagnetic and antiferromagnetic characteristics, depending on the dehydrogenation characters of the bases and their interaction modes. Hopefully, this work provides some helpful information for the understanding of different structures and properties of the di-ionized GG base pairs.
    The Journal of Physical Chemistry B 08/2013; · 3.61 Impact Factor
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    ABSTRACT: We present a density functional theory calculational study for clarifying that a 310-helix peptide can serve as a novel dual relay element to mediate long-range charge migrations via its C- and N-terminus in proteins. The ionization potential of the 310-helix C-terminus correlates inversely with the helix length, HOMO energy, and dipole moment. In particular, it decreases considerably with the increase of peptide units, even to a smaller value than that of the easily oxidized amino acid residue, which implies the possibility of releasing an electron and forming a hole at the 310-helical C-terminus. On the other hand, the electron affinity of the 310-helical N-terminus correlates positively with the helix length and dipole moment but inversely with the LUMO energy. Clearly, the increasing positive electron-binding energy with the increase of peptide units implies that the 310-helical N-terminus can capture an excess electron and play an electron-relaying role. The relaying ability of the 310-helical C-terminus and N-terminus not only depends on the helix length, but also varies subject to the capping effect, the collaboration and competition of proximal groups, and solvent environments, etc. In contrast with the known hole relays such as the side-chains of Tyr, Trp and electron relays such as the side-chains of protonated Lys and Arg, etc., either the hole relay (the 310-helix C-terminus) or the electron relay (the 310-helix N-terminus) is property-tunable and could apply to different proteins for assisting or mediating charge long-rang migrations.
    The Journal of Physical Chemistry B 05/2013; · 3.61 Impact Factor
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    ABSTRACT: We report an ab initio molecular dynamics simulation study on the accommodation of a dielectron in a pyridinium ionic liquid in both the singlet and triplet state. In contrast to water and liquid ammonia, a dielectron does not prefer to reside in cavity-shaped structures in the ionic liquid. Instead, it prefers to be distributed over more cations, with long-lived diffuse and short-lived localized distributions, and with a triplet ground state and a low-lying, open-shell singlet excited state. The two electrons evolve nonsynchronously in both states via a diffuse-versus-localized interconversion mechanism that features a dynamic bipolaron with a modest mobility, slightly lower than a hydrated electron. This work presents the first detailed study on the structures and dynamics of a dielectron in ionic liquids.
    Physical Review Letters 03/2013; 110(10):107602. · 7.73 Impact Factor
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    ABSTRACT: Density functional theory calculations were employed to study the stabilization process of the guanine radical cation through amino acid interactions as well as to understand the protection mechanisms. On the basis of our calculations, several protection mechanisms are proposed in this work subject to the type of the amino acid. Our results indicate that a series of three-electron bonds can be formed between the amino acids and the guanine radical cation which may serve as relay stations supporting hole transport. In the three-electron-bonded, π-π-stacked, and H-bonded modes, amino acids can protect guanine from oxidation or radiation damage by sharing the hole, while amino acids with reducing properties can repair the guanine radical cation through proton-coupled electron transfer or electron transfer. Another important finding is that positively charged amino acids (ArgH(+) , LysH(+) , and HisH(+) ) can inhibit ionization of guanine through raising its ionization potential. In this situation, a negative dissociation energy for hydrogen bonds in the hole-trapped and positively charged amino acid-Guanine dimer is observed, which explains the low hole-trapping efficiency. We hope that this work provides valuable information on how to protect DNA from oxidation- or radiation-induced damages in biological systems.
    ChemPhysChem 02/2013; · 3.35 Impact Factor
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    ABSTRACT: We present a combined M06 functional calculation and ab initio molecular dynamics simulation study of an excess electron (EE) in a microhydrated aromatic complex (modeled by benzene (Bz)-water binary clusters, Bz(H(2)O)(n)). Calculated results illustrate that Bz ring and water clusters are indeed linked through the π⋯HO interactions in the neutral Bz(H(2)O)(n) (n = 1-8) clusters, and the size of the water cluster does not influence the nature of its interaction with the π system for the oligo-hydrated complexes. The states and the dynamics of an EE trapped in such Bz-water clusters were also determined. All of possible localized states for the EE can be roughly classified into two types: (i) single, ring-localized states (the Bz-centered valence anions) in which an EE occupies the LUMO of the complexes originating from the LUMO (π∗) of the Bz ring, and the π⋯HO interactions are enhanced for increase of electron density of the Bz ring. In this mode, the carbon skeleton of the Bz part is significantly deformed due to increase of electron density and nonsymmetric distribution of electron density induced by the interacting H-O bonds; (ii) solvated states, in which an EE is trapped directly as a surface state by the dangling hydrogen atoms of water molecules or as a solvated state in a mixed cavity formed by Bz and water cluster. In the latter case, Bz may also participate in capturing an EE using its C-H bonds in the side edge of the aromatic ring as a part of the cavity. In general, a small water cluster is favorable to the Bz-centered valence anion state, while a large one prefers a solvated electron state. Fluctuations and rearrangement of water molecules can sufficiently modify the relative energies of the EE states to permit facile conversion from the Bz-centered to the water cluster-centered state. This indicates that aromatic Bz can be identified as a stepping stone in electron transfer and the weak π⋯HO interaction plays an important role as the driving force in conversion of the two states.
    The Journal of Chemical Physics 01/2013; 138(1):014310. · 3.12 Impact Factor
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    ABSTRACT: Graphene oxide has attracted intense research interest recently because the graphene oxide synthesis route, as a promising alternative for cost-effective mass production of graphene, has been explored. To further study the oxidation process and possible mechanism and to explore applicability of the oxidized products, we have performed a computational study on three series of oligoacene dioxides, focusing on their structures and electronic properties. Taking 1,5-dioxidized naphthalene as a starting point, three series of oligoacene dioxides are considered as follows: 1) middle insertion by 1-2 benzene rings; 2) single-side expansion using 1-2 benzene rings; 3) double-side expansion using two benzene rings. On the basis of density functional theory and complete active space self-consistent field (CASSCF) calculations, we reveal that oligoacene dioxides in the middle insertion series have a triplet ground state, whereas those in the single-side expansion series and the double-side expansion series have open-shell broken-symmetry singlet diradical ground states except for their common origin naphthalene-1,5-dioxide whose ground state is triplet and which is also viewed as the origin of the middle insertion series. Magnetic coupling interactions of these oligoacene dioxides are also determined. This work should help people toward an atomistic understanding of the electronic structures and properties of possible intermediates or products and even the oxidation mechanism of graphene sheets, and provides a reasonable strategy of designing novel graphene-oxide-based magnetic materials.
    ChemPhysChem 11/2012; · 3.35 Impact Factor
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    ABSTRACT: In the present work, cyclopentadienyl radicals are introduced to nucleobases to gain the building blocks of DNA-based molecular wires with novel electromagnetic characteristics. Calculations reveal that the radicalized DNA bases exist stably because their extended π-conjugated structures are beneficial to spin delocalization, diradical base pairs possess open-shell singlet ground states, and magnetic coupling interactions of the multiradical systems are controlled by both intra- and intermolecular interactions. For the designed base pairs, the intra-base-pair magnetic interactions are weak, especially in the diradical rA–rT base pair; as for the inter-base-pair magnetic interactions, different cases are observed depending on the relative position of the radicalized bases. The overlap-stacking diradical helices manifest variable degrees of ferromagnetic and antiferromagnetic characteristics, whereas the magnetic coupling interactions in the cross-stacking diradical helices are generally weak. The latter is attributed to the long spatial distances between the two spin centers. Thus, for the tetraradical helices, their magnetic characteristics can be viewed as a combination of two overlap-stacking diradical base pairs, and mostly are antiferromagnetic. This work provides a reasonable strategy of designing magnetic building blocks for the magnetic DNA molecular wires or DNA molecular magnets.
    The Journal of Physical Chemistry C 10/2012; 116(44):23214–23223. · 4.84 Impact Factor
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    ABSTRACT: This work presents a density functional theory calculational study for clarifying that peptide loops (-[peptide](n)-) including the N-terminal and the C-terminal oligopeptides and the α-helix N-terminal can serve as an intriguing kind of relay elements, as an addition to the known relay stations served by aromatic amino acids for electron hopping migration. For these protein motifs, an excess electron generally prefers to reside at the -NH(3)(+) group in a Rydberg state for the N-terminal peptides, or at the -COOH group in a dipole-bound state for the C-terminal peptides, and at the N-terminal in a dipole-bound π*-orbital state for the peptide loops and α-helices. The electron binding ability can be effectively enhanced by elongation for the α-helix N-terminal, and by bending, twisting, and even β-turning for the peptide chains. The relay property is determined by the local dipole instead of the total dipole of the peptide chains. Although no direct experiment supports this hypothesis, a series of recent studies regarding charge hopping migration associated with the peptide chains and helices could be viewed as strong evidence. But, further studies are still needed by considering the effects from relative redox potential between the donor and acceptor sites, protein environment, and structure water molecules.
    Physical Chemistry Chemical Physics 10/2012; · 4.20 Impact Factor
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    ABSTRACT: Metal-modified DNA base pairs, which possess potential electrical conductivity and can serve as conductive nanomaterials, have recently attracted much attention. Inspired by our recent finding that multicopper incorporation into natural DNA base pairs could improve the electronic properties of base pairs, herein, we designed two novel multi-copper-mediated mismatched base pairs (G(3Cu) T and A(2Cu) C), and examined their structural and electronic properties by means of density functional theory calculations. The results reveal that these multi-Cu-mediated mismatched base pairs still have planar geometries that are thermodynamically favorable to stability, and their binding energies are close to those of multi-Cu-mediated normal base pairs (G(3Cu) C and A(2Cu) T). Their HOMO-LUMO gaps and ionization potentials decrease significantly compared to the corresponding natural base pairs. As evidenced by the charge transfer excitation transitions, transverse electronic communication of G(3Cu) T and A(2Cu) C is remarkably enhanced, suggesting that they facilitate electron migration along the DNA wires upon incorporation. Further examinations also clarify the possibility to build promising DNA helices using the G(3Cu) T and/or A(2Cu) C base pairs. The calculated electronic properties of the three-layer-stacked multi-Cu-mediated mismatched base pairs illustrate that the Cu(m) -DNA have better conductivity. This work provides perspectives for the development and application of DNA nanowires.
    ChemPhysChem 07/2012; 13(14):3293-302. · 3.35 Impact Factor
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    ABSTRACT: The microhydration of the complexes formed by trivalent metal ions (Al3+, Ga3+, In3+) and zwitterionic glycine biomolecule has been investigated systematically by first-principles calculations. A first solvation shell with a hexacoordinate configuration is found to occur at the metal center due to the delicate equilibrium between the steric hindrance and the charge transfer from the ligands to the metal. The hydrogen bond forms between the water ligand and glycine bioligand in the first solvation shell, providing an energetically favorable pathway for the proton transfer from the inner shell to the outer shell.
    Chemical Physics Letters 06/2012; 537:101–106. · 2.15 Impact Factor
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    ABSTRACT: Three classes of multi-Zn-expanded graphene patches in different shapes are computationally designed through introducing a Zn chain into the corresponding middle benzenoid chain. Both density functional theory and complete active space self-consistent field calculations predict that molecules of nnn-quasi-linear and nnn-slightly bent series have the open-shell broken-symmetry (BS) singlet diradical ground states, whereas those of n(n+1)n species possess quintet tetraradical as their ground state and become open-shell BS singlet tetraradicals when they are in a higher energy state. These results offer the first theoretical attempt to introduce multi-Zn into the small graphene patches to form Zn-expanded graphene patches, leading them to polyradical structures. This work provides an executable strategy to yield molecules which have stable polyradicaloid character and enhanced electronic properties of multi-Zn-expanded graphene patches.
    Journal of Computational Chemistry 05/2012; 33(21):1773-80. · 3.84 Impact Factor

Publication Stats

353 Citations
411.36 Total Impact Points

Institutions

  • 1996–2014
    • Shandong University
      • • Department of Chemical Engineering
      • • Institute of Theoretical Chemistry
      • • Key Laboratory for Colloid and Interface Chemistry
      Chi-nan-shih, Shandong Sheng, China
  • 2013
    • Government of the People's Republic of China
      Peping, Beijing, China
  • 1994–2011
    • Qufu Normal University
      Küfow, Shandong Sheng, China
  • 2005–2009
    • Michigan State University
      • Department of Chemistry
      East Lansing, MI, United States
  • 2007
    • Albany State University
      • Department of Natural Sciences
      Albany, GA, United States
  • 2001–2005
    • University of Jinan (Jinan, China)
      Chi-nan-shih, Shandong Sheng, China
  • 2000
    • The University of Hong Kong
      Hong Kong, Hong Kong