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Cheng S, Yang J. A Theoretical Study of Organotin Binding in Aromatase. Int J Mol Sci 2023; 24:ijms24108954. [PMID: 37240300 DOI: 10.3390/ijms24108954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/11/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
The widely used organotin compounds are notorious for their acute toxicity. Experiments revealed that organotin might cause reproductive toxicity by reversibly inhibiting animal aromatase functioning. However, the inhibition mechanism is obscure, especially at the molecular level. Compared to experimental methods, theoretical approaches via computational simulations can help to gain a microscopic view of the mechanism. Here, in an initial attempt to uncover the mechanism, we combined molecular docking and classical molecular dynamics to investigate the binding between organotins and aromatase. The energetics analysis indicated that the van der Waals interaction is the primary driving force of binding the organic tail of organotin and the aromatase center. The hydrogen bond linkage trajectory analysis revealed that water plays a significant role in linking the ligand-water-protein triangle network. As an initial step in studying the mechanism of organotin inhibiting aromatase, this work provides an in-depth understanding of the binding mechanism of organotin. Further, our study will help to develop effective and environmentally friendly methods to treat animals that have already been contaminated by organotin, as well as sustainable solutions for organotin degradation.
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Affiliation(s)
- Shuming Cheng
- School of Chemical Engineering and Technology, Sun Yat-Sen University, Zhuhai 519082, China
| | - Jing Yang
- School of Chemical Engineering and Technology, Sun Yat-Sen University, Zhuhai 519082, China
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2
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Skitnevskaya AD, Gokhberg K, Trofimov AB, Grigoricheva EK, Kuleff AI, Cederbaum LS. Two-Sided Impact of Water on the Relaxation of Inner-Valence Vacancies of Biologically Relevant Molecules. J Phys Chem Lett 2023; 14:1418-1426. [PMID: 36731025 DOI: 10.1021/acs.jpclett.2c03654] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
After ionization of an inner-valence electron of molecules, the resulting cation-radicals store substantial internal energy which, if sufficient, can trigger ejection of an additional electron in an Auger decay usually followed by molecule fragmentation. In the environment, intermolecular Coulombic decay (ICD) and electron-transfer mediated decay (ETMD) are also operative, resulting in one or two electrons being ejected from a neighbor, thus preventing the fragmentation of the initially ionized molecule. These relaxation processes are investigated theoretically for prototypical heterocycle-water complexes of imidazole, pyrrole, and pyridine. It is found that the hydrogen-bonding site of the water molecule critically influences the nature and energetics of the electronic states involved, opening or closing certain relaxation processes of the inner-valence ionized system. Our results indicate that the relaxation mechanisms of biologically relevant systems with inner-valence vacancies on their carbon atoms can strongly depend on the presence of the electron-density donating or accepting neighbor, either water or another biomolecule.
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Affiliation(s)
- Anna D Skitnevskaya
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - Kirill Gokhberg
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
| | - Alexander B Trofimov
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
- Favorsky's Institute of Chemistry, SB RAS, Favorsky Str. 1, 664033 Irkutsk, Russia
| | - Emma K Grigoricheva
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
- Laboratory of Quantum Chemical Modeling of Molecular Systems, Irkutsk State University, Karl Marx Str. 1, 664003 Irkutsk, Russia
| | - Alexander I Kuleff
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
| | - Lorenz S Cederbaum
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Heidelberg 69120, Germany
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3
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Zhao F, Feng YJ, Liu YR, Jiang S, Huang T, Wang ZH, Xu CX, Huang W. Enhancement of Atmospheric Nucleation by Highly Oxygenated Organic Molecules: A Density Functional Theory Study. J Phys Chem A 2019; 123:5367-5377. [PMID: 31199633 DOI: 10.1021/acs.jpca.9b03142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
New particle formation (NPF) by gas-particle conversion is the main source of atmospheric aerosols. Highly oxygenated organic molecules (HOMs) and sulfuric acid (SA) are important NPF participants. 2-Methylglyceric acid (MGA), a kind of HOMs, is a tracer of isoprene-derived secondary organic aerosols. The nucleation mechanisms of MGA with SA were studied using density functional theory and atmospheric cluster dynamics simulation in this study, along with that of MGA with methanesulfonic acid (MSA) as a comparison. Our theoretical works indicate that the (MGA)(SA) and (MGA)(MSA) clusters are the most stable ones in the (MGA) i(SA) j ( i = 1-2, j = 1-2) and (MGA) i(MSA) j ( i = 1-2, j = 1-2) clusters, respectively. Both the formation rates of (MGA)(SA) and (MGA)(MSA) clusters are quite large and could have significant contributions to NPF. The results imply that the homomolecular nucleation of MGA is unlikely to occur in the atmosphere, and MGA and SA can effectively contribute to heteromolecular nucleation mainly in the form of heterodimers. MSA exhibits properties similar to SA in its ability to form clusters with MGA but is slightly weaker than SA.
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Affiliation(s)
- Feng Zhao
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics , Chinese Academy of Sciences , Hefei , Anhui 230031 , China.,School of Information Science and Technology , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Ya-Juan Feng
- School of Information Science and Technology , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Yi-Rong Liu
- School of Information Science and Technology , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Shuai Jiang
- School of Information Science and Technology , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Teng Huang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics , Chinese Academy of Sciences , Hefei , Anhui 230031 , China
| | - Zi-Hang Wang
- School of Information Science and Technology , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Cai-Xin Xu
- School of Information Science and Technology , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Wei Huang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics , Chinese Academy of Sciences , Hefei , Anhui 230031 , China.,School of Information Science and Technology , University of Science and Technology of China , Hefei , Anhui 230026 , China.,Center for Excellent in Urban Atmospheric Environment, Institute of Urban Environment , Chinese Academy of Sciences , Xiamen , Fujian 361021 , China
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4
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Sarkar S, Ramanathan N, Sruthi PK, Sundararajan K. Conformations of diethyl ether and its interaction with pyrrole at low temperatures. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 213:361-369. [PMID: 30721851 DOI: 10.1016/j.saa.2019.01.076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/25/2019] [Accepted: 01/26/2019] [Indexed: 06/09/2023]
Abstract
Conformations of diethyl ether (DEE) were studied at low temperatures in N2 and Ar matrixes. Computations performed at B3LYP/aug-cc-pVDZ level of theory yielded three minima corresponding to tt, tg± and g±g± conformers of DEE. Of the three, the tt and tg± conformers of DEE were experimentally identified in N2 and Ar matrixes. Furthermore, hydrogen bonded complexes of pyrrole (py) with DEE have been investigated using Density Functional Theory (DFT) and matrix isolation infrared spectroscopy. Computations performed at B3LYP level of theory using aug-cc-pVDZ basis set on pyrrole with tt and tg± conformers of DEE gave py-DEE-tt and py-DEE-tg± complexes, both characterized by NH⋯O interaction. Experimental evidence for the formation of py-DEE-tt and py-DEE-tg± complexes was affirmed from the shifts in the NH stretching, NH bending regions of pyrrole and COC and CH stretching regions of DEE. NBO analysis was carried out to understand the charge-transfer delocalization interactions in the conformers of DEE and its hydrogen bonded complexes.
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Affiliation(s)
- Shubhra Sarkar
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - N Ramanathan
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - P K Sruthi
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - K Sundararajan
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India.
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5
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Choudhary A, Chandra A. Dynamics of water in conical solvation shells around a benzene solute under different thermodynamic conditions. Phys Chem Chem Phys 2018; 20:18328-18339. [PMID: 29938274 DOI: 10.1039/c7cp08109j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water molecules in different parts of the anisotropic hydration shell of an aromatic molecule experience different interactions. In the present study, we investigate the anisotropic dynamics of water molecules in different non-overlapping conical shells around a benzene solute at sub- and supercritical conditions by means of molecular dynamics simulations using both non-polarizable and polarizable models. In addition to the dynamical properties, the effects of polarizability on the hydration structure of benzene at varying thermodynamic conditions are also investigated in the current study. The presence of πH-bonding in the solvation shell is found to be an important factor that influences the anisotropic dynamics of the benzene hydration shell. The water molecules located axial to the benzene plane are found to be maximally influenced by the πH-bonding. The extent of πH-bonding is found to be somewhat reduced on inclusion of polarizability. The πH-bonded water molecules are found to reorient through large-amplitude angular jumps where the jump-angle amplitude increases at higher temperatures and lower densities. For both non-polarizable and polarizable models, it is found that the water molecules in the axial conical shells possess faster orientational and hydrogen bond dynamics compared to those in the equatorial plane. Water molecules in the axial conical shells are also found to diffuse at a faster rate than bulk molecules due to the relatively weaker benzene-water πH-bonding interactions in the axial region of the hydration shell. The residence dynamics of water molecules in different conical solvation shells around the solute is also investigated in the current study.
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Affiliation(s)
- Ashu Choudhary
- Department of Chemistry, Indian Institute of Technology Kanpur, 208016, India.
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6
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Sarkar S, Ramanathan N, Sundararajan K. Effect of Methyl Substitution on the N–H···O Interaction in Complexes of Pyrrole with Water, Methanol, and Dimethyl Ether: Matrix Isolation Infrared Spectroscopy and ab Initio Computational Studies. J Phys Chem A 2018; 122:2445-2460. [DOI: 10.1021/acs.jpca.8b00023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shubhra Sarkar
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
- Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - N. Ramanathan
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
- Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - K. Sundararajan
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
- Homi Bhabha National Institute, Kalpakkam 603 102, India
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7
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Han YJ, Feng YJ, Miao SK, Jiang S, Liu YR, Wang CY, Chen J, Wang ZQ, Huang T, Li J, Huang W. Hydration of 3-hydroxy-4,4-dimethylglutaric acid with dimethylamine complex and its atmospheric implications. Phys Chem Chem Phys 2018; 20:25780-25791. [DOI: 10.1039/c8cp04029j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Changes in temperature affects the distribution of isomers, which facilitates the understanding of new particle formation in the atmosphere.
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8
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Feng H, Gao W, Su L, Sun Z, Chen L. MD simulation study of the diffusion and local structure of n-alkanes in liquid and supercritical methanol at infinite dilution. J Mol Model 2017; 23:195. [PMID: 28560578 DOI: 10.1007/s00894-017-3366-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 05/09/2017] [Indexed: 10/19/2022]
Abstract
The diffusion coefficients of 14 n-alkanes (ranging from methane to n-tetradecane) in liquid and supercritical methanol at infinite dilution (at a pressure of 10.5 MPa and at temperatures of 299 K and 515 K) were deduced via molecular dynamics simulations. Values for the radial distribution function, coordination number, and number of hydrogen bonds were then calculated to explore the local structure of each fluid. The flexibility of the n-alkane (as characterized by the computed dihedral distribution, end-to-end distance, and radius of gyration) was found to be a major influence and hydrogen bonding to be a minor influence on the local structure. Hydrogen bonding reduces the flexibility of the n-alkane, whereas increasing the temperature enhances its flexibility, with temperature having a greater effect than hydrogen bonding on flexibility. Graphical abstract The flexibility of the alkane is a major influence and the hydrogen bonding is a minor influence on the first solvation shell; the coordination numbers of long-chain n-alkanes in the first solvation shell are rather low.
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Affiliation(s)
- Huajie Feng
- School of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, 571158, People's Republic of China
| | - Wei Gao
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, People's Republic of China
| | - Li Su
- Hainan Entry-Exit Inspection and Quarantine Technology Center, Haikou, 570311, People's Republic of China
| | - Zhenfan Sun
- School of Chemistry and Chemical Engineering, Hainan Normal University, Haikou, 571158, People's Republic of China.
| | - Liuping Chen
- KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
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9
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Ma Y, Chen J, Jiang S, Liu YR, Huang T, Miao SK, Wang CY, Huang W. Characterization of the nucleation precursor (H2SO4–(CH3)2NH) complex: intra-cluster interactions and atmospheric relevance. RSC Adv 2016. [DOI: 10.1039/c5ra22887e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amines have been proposed to participate in the nucleation process, but the electron density analysis and the determination of a temperature dependence of the clusters are still lacking.
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Affiliation(s)
- Yan Ma
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Jiao Chen
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Shuai Jiang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Yi-Rong Liu
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Teng Huang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Shou-Kui Miao
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Chun-Yu Wang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | - Wei Huang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics & Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
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10
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Lv SS, Liu YR, Huang T, Feng YJ, Jiang S, Huang W. Stability of Hydrated Methylamine: Structural Characteristics and H2N···H–O Hydrogen Bonds. J Phys Chem A 2015; 119:3770-9. [DOI: 10.1021/acs.jpca.5b00616] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sha-Sha Lv
- School
of Physics and Materials Science, Anhui University, Hefei, Anhui 230601, China
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Yi-Rong Liu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- School of Environmental Science & Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Teng Huang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- School of Environmental Science & Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ya-Juan Feng
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- School of Environmental Science & Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shuai Jiang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- School of Environmental Science & Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei Huang
- School
of Physics and Materials Science, Anhui University, Hefei, Anhui 230601, China
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics & Fine Mechanics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- School of Environmental Science & Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
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11
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Hussain HB, Wilson KA, Wetmore SD. Serine and Cysteine π-Interactions in Nature: A Comparison of the Frequency, Structure, and Stability of Contacts Involving Oxygen and Sulfur. Aust J Chem 2015. [DOI: 10.1071/ch14598] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Despite many DNA–protein π-interactions in high-resolution crystal structures, only four X–H···π or X···π interactions were found between serine (Ser) or cysteine (Cys) and DNA nucleobase π-systems in over 100 DNA–protein complexes (where X = O for Ser and X = S for Cys). Nevertheless, 126 non-covalent contacts occur between Ser or Cys and the aromatic amino acids in many binding arrangements within proteins. Furthermore, Ser and Cys protein–protein π-interactions occur with similar frequencies and strengths. Most importantly, due to the great stability that can be provided to biological macromolecules (up to –20 kJ mol–1 for neutral π-systems or –40 kJ mol–1 for cationic π-systems), Ser and Cys π-interactions should be considered when analyzing protein stability and function.
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12
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Janjić GV, Malkov SN, Zivković MV, Zarić SD. What are preferred water-aromatic interactions in proteins and crystal structures of small molecules? Phys Chem Chem Phys 2014; 16:23549-53. [PMID: 25271703 DOI: 10.1039/c4cp00929k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The distribution of water molecules around aromatic rings in the protein structures and crystal structures of small molecules shows quite a small number of the strongest OH-π interactions, a larger number of parallel interactions, and the largest number of the weakest CH-O interactions.
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Affiliation(s)
- Goran V Janjić
- Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, P.O. Box 473, Belgrade, Serbia
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13
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Vojislavljević-Vasilev DZ, Janjić GV, Medaković VB, Blagojević JP, Zarić SD. Parallel water/aromatic interactions of non-coordinated and coordinated water. Chemphyschem 2014; 15:2386-96. [PMID: 24840235 DOI: 10.1002/cphc.201402004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/19/2014] [Indexed: 11/07/2022]
Abstract
The parallel interactions of non-coordinated and coordinated water molecules with an aromatic ring were studied by analyzing data in the Cambridge structural database (CSD) and by using quantum chemical calculations. The CSD data show that water/aromatic contacts prefer parallel to OH/π interactions, which indicates the importance of parallel interactions. The results reveal the influence of water coordination to a metal ion; the interactions of aqua complexes are stronger. Coordinated water molecules prefer a parallel-down orientation in which one OH bond is parallel to the aromatic ring, whereas the other OH bond points to the plane of the ring. The interactions of aqua complexes with parallel-down water/benzene orientation are as strong as the much better known OH/π orientations. The strongest calculated interaction energy is -14.89 kcal mol(-1) . The large number of parallel contacts in crystal structures and the quite strong interactions indicate the importance of parallel orientation in water/benzene interactions.
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14
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Structural flexibility of 4,4'-methylene diphenyl diisocyanate (4,4'-MDI): evidence from first principles calculations. J Mol Model 2014; 20:2097. [PMID: 24522379 PMCID: PMC3936137 DOI: 10.1007/s00894-014-2097-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/25/2013] [Indexed: 11/23/2022]
Abstract
A reactant used globally in the production of polyurethane is the molecule 4,4′-methylene diphenyl diisocyanate (4,4′-MDI). The structural flexibility of 4,4′-MDI is one of the most important molecular properties influencing the polymerization process and this property was therefore modeled using density functional theory (DFT) calculations and Car-Parrinello molecular dynamics (MD) simulations. Global and local minima structures were found and confirmed by vibrational analysis. The energy barriers related to rotation of the aromatic rings were estimated by DFT calculations. The stability of global and local minima was verified by Car-Parrinello (MD) runs at finite temperature. The presence of weak C–H⋯π hydrogen bonds was confirmed by atoms in molecules analysis and found to be responsible for the low energy barriers.
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