Exploring the difference of bonding strength between silver(i) and chalcogenides in block copolymer systems

2020 ◽  
Vol 11 (44) ◽  
pp. 7087-7093
Author(s):  
Peng Zhao ◽  
Cong-Qiao Xu ◽  
Chenxing Sun ◽  
Jiahao Xia ◽  
Lin Sun ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Bond Strength ◽  
Single Molecule ◽  
Bonding Strength ◽  
Quantum Chemical ◽  
Force Spectroscopy ◽  
Single Molecule Force Spectroscopy ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
The Difference

The order of Ag(i)–S < Ag(i)–Se < Ag(i)–Te bond strength was confirmed by single-molecule force spectroscopy (SMFS) with quantum chemical studies.

Single-Molecule Force Spectroscopy of Selenium-Containing Amphiphilic Block Copolymer: Toward Disassembling the Polymer Micelles

Langmuir ◽  
2012 ◽  
Vol 28 (25) ◽  
pp. 9601-9605 ◽  
Author(s):  
Xinxin Tan ◽  
Ying Yu ◽  
Kai Liu ◽  
Huaping Xu ◽  
Dongsheng Liu ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Single Molecule ◽  
Force Spectroscopy ◽  
Amphiphilic Block Copolymer ◽  
Polymer Micelles ◽  
Single Molecule Force Spectroscopy

scholarly journals Biomechanical Characterization of SARS-CoV-2 Spike RBD and Human ACE2 Protein-Protein Interaction

2020 ◽  
Author(s):  
Wenpeng Cao ◽  
Chuqiao Dong ◽  
Seonghan Kim ◽  
Decheng Hou ◽  
Wanbo Tai ◽  
...  
Keyword(s):  
Single Molecule ◽  
Force Spectroscopy ◽  
Cell Types ◽  
Single Molecule Force Spectroscopy ◽  
S Protein ◽  
Angiotensin Converting Enzyme 2 ◽  
Loading Rates ◽  
Protein Protein Interaction ◽  
Biophysical Mechanism ◽  
The Difference

The current COVID-19 pandemic has already had a devastating impact across the world. SARS-CoV-2 (the virus causing COVID-19) is known to use its surface spike (S) protein's receptor binding domain (RBD) to interact with the angiotensin-converting enzyme 2 (ACE2) receptor expressed on many human cell types. The RBD–ACE2 interaction is a crucial step to mediate the host cell entry of SARS-CoV-2. Recent studies indicate that the ACE2 interaction with the SARS-CoV-2 S protein has higher affinity than its binding with the structurally identical S protein of SARS-CoV-1, the virus causing the 2002-2004 SARS epidemic. However, the biophysical mechanism behind such binding affinity difference is unclear. This study utilizes a combined single-molecule force spectroscopy and steered molecular dynamics (SMD) simulation approach to quantify the specific interactions between CoV-2 or CoV-1 RBD and ACE2. Depending on the loading rates, the unbinding forces between CoV-2 RBD and ACE2 range from 70 to 110 pN, and are 30-50% higher than those of CoV-1 RBD and ACE2 under similar loading rates. SMD results indicate that CoV-2 RBD interacts with the N-linked glycan on Asn90 of ACE2. This interaction is mostly absent in the CoV-1 RBD–ACE2 complex. During the SMD simulations, the extra RBD-N-glycan interaction contributes to a greater force and prolonged interaction lifetime. The observation is confirmed by our experimental force spectroscopy study. After the removal of N-linked glycans on ACE2, its mechanical binding strength with CoV-2 RBD decreases to a similar level of the CoV-1 RBD–ACE2 interaction. Together, the study uncovers the mechanism behind the difference in ACE2 binding between SARS-CoV-2 and SARS-CoV-1, and could aid in the development of new strategies to block SARS-CoV-2 entry.

scholarly journals LexA-DNA Bond Strength by Single Molecule Force Spectroscopy

2004 ◽  
Vol 87 (4) ◽  
pp. 2683-2690 ◽  
Author(s):  
F. Kühner ◽  
L.T. Costa ◽  
P.M. Bisch ◽  
S. Thalhammer ◽  
W.M. Heckl ◽  
...  
Keyword(s):  
Bond Strength ◽  
Single Molecule ◽  
Force Spectroscopy ◽  
Single Molecule Force Spectroscopy

Quantum Chemical Studies of Hole Transfer in Liquid Hexane

2017 ◽  
Vol 137 (7) ◽  
pp. 435-441
Author(s):  
Masahiro Sato ◽  
Akiko Kumada ◽  
Kunihiko Hidaka ◽  
Toshiyuki Hirano ◽  
Fumitoshi Sato
Keyword(s):  
Quantum Chemical ◽  
Hole Transfer ◽  
Chemical Studies ◽  
Quantum Chemical Studies

ESR, spectroscopic, and quantum-chemical studies on the electronic structures of complexes formed by Cu(I) with radicals

1986 ◽  
Vol 22 (1) ◽  
pp. 27-33
Author(s):  
N. P. Gritsan ◽  
O. M. Usov ◽  
N. V. Shokhirev ◽  
I. V. Khmelinskii ◽  
V. F. Plyusnin ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Quantum Chemical ◽  
Chemical Studies ◽  
Quantum Chemical Studies

scholarly journals Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 497
Author(s):  
Ewa D. Raczyńska
Keyword(s):  
Aqueous Solution ◽  
Quantum Chemical ◽  
Biologically Active ◽  
Deprotonation Reaction ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Scanty Information ◽  
Derivatives Of ◽  
Common Anion ◽  
Tautomeric Mixture

Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books appeared in the last 50 years. Quite a different situation takes place for derivatives of biologically active azulene, for which only scanty information on this phenomenon can be found in the literature. In this work, quantum-chemical studies have been undertaken for symmetrically and unsymmetrically substituted azulenols (constitutional isomers of naphthols). Stabilities of two enol (OH) rotamers and all possible keto (CH) tautomers have been analyzed in the gas phase {DFT(B3LYP)/6-311+G(d,p)} and also in aqueous solution {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. Contrary to naphthols, for which the keto forms can be neglected, at least one keto isomer (C1H, C2H, and/or C3H) contributes significantly to the tautomeric mixture of each azulenol to a higher degree in vacuo (non-polar environment) than in water (polar amphoteric solvent). The highest amounts of the CH forms have been found for 2- and 5-hydroxyazulenes, and the smallest ones for 1- and 6-hydroxy derivatives. The keto tautomer(s), together with the enol rotamers, can also participate in deprotonation reaction leading to a common anion and influence its acid-base properties. The strongest acidity in vacuo exhibits 6-hydroxyazulene, and the weakest one displays 1-hydroxyazulene, but all azulenols are stronger acids than phenol and naphthols. Bond length alternation in all DFT-optimized structures has been measured using the harmonic oscillator model of electron delocalization (HOMED) index. Generally, the HOMED values decrease for the keto tautomers, particularly for the ring containing the labile proton. Even for the keto tautomers possessing energetic parameters close to those of the enol isomers, the HOMED indices are low. However, some kind of parallelism exists for the keto forms between their relative energies and HOMEDs estimated for the entire molecules.

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