| 1. |
- Zhan, Shaoqi, et al.
(författare)
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Dynamics with Explicit Solvation Reveals Formation of the Prereactive Dimer as Sole Determining Factor for the Efficiency of Ru(bda)L-2 Catalysts
- 2018
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Ingår i: ACS Catalysis. - : AMER CHEMICAL SOC. - 2155-5435. ; 8:9, s. 8642-8648
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Tidskriftsartikel (refereegranskat)abstract
- This report describes all key steps in the O-O bond formation from two separated [Ru-V=O(bda)L-2](+) cations to form the dinuclear [(bda)L2RuIV-O-Ru-IV(bda)L-2](2+) in explicit solvent. The three steps involve the diffusion of the catalysts in the water phase, formation of the prereactive dimer, and the bond formation between the two catalysts. On the basis of the calculated parameters, we compute the rate constant of two catalysts with different L-ligands, isoquinoline and picoline, and the computed values are in excellent agreement with the experimental ones. The interaction of the axial ligands is key to the improved rates of the larger ligand, mainly by facilitating the formation of the prereactive dimer from the solvated monomer. By comparing the binding free energy of hydrophilic Ru-IV-OH and hydrophobic Ru-V=O, the hydrophobic driving force of Ru-V=O in this system has been estimated to 1 kcal mol(-1).
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| 2. |
- Zhu, X., et al.
(författare)
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A supramolecular peptide polymer from hydrogen-bond and coordination-driven self-assembly
- 2018
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry. - 1759-9954 .- 1759-9962. ; 9:1, s. 69-76
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Tidskriftsartikel (refereegranskat)abstract
- A terpyridine- and guanine-functionalized peptide was developed that could form different morphologies by self-assembly or coordination with Fe2+ in dimethyl sulfoxide. The self-assembly of the peptide is attributed to the G-quartet formation of a guanine moiety and intermolecular terpyridine π-π stacking. Upon the addition of Fe2+, a Fe2+-(terpyridine)2 complex is formed that turns the square-planar self-assembly to a three-dimensional self-assembly. As a consequence, a variety of interesting morphologies and chemical properties were observed. The self-assembled polymers were studied by nuclear magnetic resonance spectroscopy, ultraviolet-visible and fluorescence spectroscopy, viscosity measurement, circular dichroism, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and atomic force microscopy. This external stimuli driven self-assembly of a peptide may be further applied to drug delivery applications.
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| 3. |
- Zou, Rongfeng, et al.
(författare)
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Activity of Antimicrobial Peptide Aggregates Decreases with Increased Cell Membrane Embedding Free Energy Cost
- 2018
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Ingår i: Biochemistry. - : AMER CHEMICAL SOC. - 0006-2960 .- 1520-4995. ; 57:18, s. 2606-2610
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial peptides (AMPs) are a promising alternative to antibiotics for mitigating bacterial infections, in light of increasing bacterial resistance to antibiotics. However, predicting, understanding, and controlling the antibacterial activity of AMPs remain a significant challenge. While peptide intramolecular interactions are known to modulate AMP antimicrobial activity, peptide intermolecular interactions remain elusive in their impact on peptide bioactivity. Herein, we test the relationship between AMP intermolecular interactions and antibacterial efficacy by controlling AMP intermolecular hydrophobic and hydrogen bonding interactions. Molecular dynamics simulations and Gibbs free energy calculations in concert with experimental assays show that increasing intermolecular interactions via interpeptide aggregation increases the energy cost for the peptide to embed into the bacterial cell membrane, which in turn decreases the AMP antibacterial activity. Our findings provide a route for predicting and controlling the antibacterial activity of AMPs against Gram-negative bacteria via reductions of intermolecular AMP interactions.
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