1
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Chew PY, Joseph JA, Collepardo-Guevara R, Reinhardt A. Aromatic and arginine content drives multiphasic condensation of protein-RNA mixtures. Biophys J 2024; 123:1342-1355. [PMID: 37408305 PMCID: PMC11163273 DOI: 10.1016/j.bpj.2023.06.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/20/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023] Open
Abstract
Multiphasic architectures are found ubiquitously in biomolecular condensates and are thought to have important implications for the organization of multiple chemical reactions within the same compartment. Many of these multiphasic condensates contain RNA in addition to proteins. Here, we investigate the importance of different interactions in multiphasic condensates comprising two different proteins and RNA using computer simulations with a residue-resolution coarse-grained model of proteins and RNA. We find that in multilayered condensates containing RNA in both phases, protein-RNA interactions dominate, with aromatic residues and arginine forming the key stabilizing interactions. The total aromatic and arginine content of the two proteins must be appreciably different for distinct phases to form, and we show that this difference increases as the system is driven toward greater multiphasicity. Using the trends observed in the different interaction energies of this system, we demonstrate that we can also construct multilayered condensates with RNA preferentially concentrated in one phase. The "rules" identified can thus enable the design of synthetic multiphasic condensates to facilitate further study of their organization and function.
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Affiliation(s)
- Pin Yu Chew
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jerelle A Joseph
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey
| | - Rosana Collepardo-Guevara
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; Department of Physics, University of Cambridge, Cambridge, United Kingdom; Department of Genetics, University of Cambridge, Cambridge, United Kingdom.
| | - Aleks Reinhardt
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.
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2
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Xu B, Cui W, Tao L, Yang L, Zhao X. Risk mitigation strategy and mechanism analysis of neonicotinoid pesticides on earthworms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 347:123719. [PMID: 38458525 DOI: 10.1016/j.envpol.2024.123719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 03/10/2024]
Abstract
Neonicotinoid insecticides (NNIs) are a new class of widely used insecticides with certain risks to non-target organisms, like earthworms. The gray correlation method was used to calculate the comprehensive risk effect value of acute toxicity (LC50) and bioaccumulation (logKow) of NNIs on earthworms. A comprehensive effects three-dimensional quantitative structure-activity relationship (3D-QSAR) model was constructed, using NNIs molecular structures and the comprehensive effect value as the independent and dependent variables, respectively. One of the representatives guadipyr (GUA) was selected as the template molecule for the molecular design and modification. A total of 63 NNIs alternatives were designed with a reduced comprehensive value higher than 10%, and as high as 42%. After screening, 15 NNIs alternatives were screened with decreased acute toxicity to earthworms, bioaccumulation effects and improved functional property. The calculated primary acute risk quotient of earthworms shows that the designed NNIs alternatives have lower earthworm risks (reduction of 70.48-99.99%). Results also found that the electronic, geometric and topological parameters of NNIs are the key descriptors that affect NNIs alternatives' toxicity. The number of hydrophobic interaction amino acid residues in NNIs molecules also contributes to the acute toxicity and the bioaccumulation of NNIs alternatives on earthworms. This study aims to design and screen functionally improved and environmentally friendly NNIs alternatives that have low risk to earthworms and provide theoretical methods and new ideas for the risk control and development of pesticides represented by NNIs.
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Affiliation(s)
- Bohan Xu
- College of Resources and Environment, Jilin Agricultural University, Changchun, 130118, China.
| | - Weihan Cui
- College of Resources and Environment, Jilin Agricultural University, Changchun, 130118, China.
| | - Li Tao
- College of Resources and Environment, Jilin Agricultural University, Changchun, 130118, China.
| | - Luze Yang
- College of Resources and Environment, Jilin Agricultural University, Changchun, 130118, China.
| | - Xingmin Zhao
- College of Resources and Environment, Jilin Agricultural University, Changchun, 130118, China.
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3
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Banayan NE, Loughlin BJ, Singh S, Forouhar F, Lu G, Wong K, Neky M, Hunt HS, Bateman LB, Tamez A, Handelman SK, Price WN, Hunt JF. Systematic enhancement of protein crystallization efficiency by bulk lysine-to-arginine (KR) substitution. Protein Sci 2024; 33:e4898. [PMID: 38358135 PMCID: PMC10868448 DOI: 10.1002/pro.4898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 01/01/2024] [Accepted: 01/02/2024] [Indexed: 02/16/2024]
Abstract
Structural genomics consortia established that protein crystallization is the primary obstacle to structure determination using x-ray crystallography. We previously demonstrated that crystallization propensity is systematically related to primary sequence, and we subsequently performed computational analyses showing that arginine is the most overrepresented amino acid in crystal-packing interfaces in the Protein Data Bank. Given the similar physicochemical characteristics of arginine and lysine, we hypothesized that multiple lysine-to-arginine (KR) substitutions should improve crystallization. To test this hypothesis, we developed software that ranks lysine sites in a target protein based on the redundancy-corrected KR substitution frequency in homologs. This software can be run interactively on the worldwide web at https://www.pxengineering.org/. We demonstrate that three unrelated single-domain proteins can tolerate 5-11 KR substitutions with at most minor destabilization, and, for two of these three proteins, the construct with the largest number of KR substitutions exhibits significantly enhanced crystallization propensity. This approach rapidly produced a 1.9 Å crystal structure of a human protein domain refractory to crystallization with its native sequence. Structures from Bulk KR-substituted domains show the engineered arginine residues frequently make hydrogen-bonds across crystal-packing interfaces. We thus demonstrate that Bulk KR substitution represents a rational and efficient method for probabilistic engineering of protein surface properties to improve crystallization.
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Affiliation(s)
- Nooriel E. Banayan
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Blaine J. Loughlin
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Shikha Singh
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Farhad Forouhar
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Guanqi Lu
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
| | - Kam‐Ho Wong
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
Vaccine Research and DevelopmentPfizer Inc.Pearl RiverNew YorkUSA
| | - Matthew Neky
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
Columbia UniversityNew YorkNew YorkUSA
| | - Henry S. Hunt
- Department of PhysicsStanford UniversityStanfordCaliforniaUSA
| | | | | | - Samuel K. Handelman
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
Department of Pain & Neuronal HealthEli Lily & Co.893 Delaware StIndianapolisIndianaUSA
| | - W. Nicholson Price
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
- Present address:
University of Michigan Law SchoolAnn ArborMichiganUSA
| | - John F. Hunt
- Department of Biological Sciences702A Sherman Fairchild Center, MC2434, Columbia UniversityNew YorkNew YorkUSA
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4
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Borba JRBDM, de Araújo LP, Veloso MP, da Silveira NJF. Applying the bioisosterism strategy to obtain lead compounds against SARS-CoV-2 cysteine proteases: An in-silico approach. J Comput Chem 2024; 45:35-46. [PMID: 37641955 DOI: 10.1002/jcc.27217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/17/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023]
Abstract
SARS-CoV-2 cysteine proteases are essential nonstructural proteins due to their role in the formation of the virus multiple enzyme replication-transcription complex. As a result, those functional proteins are extremely relevant targets in the development of a new drug candidate to fight COVID-19. Based on this fact and guided by the bioisosterism strategy, the present work has selected 126 out of 1050 ligands from DrugBank website. Subsequently, 831 chemical analogs containing bioisosteres, some of which became structurally simplified, were created using the MB-Isoster software, and molecular docking simulations were performed using AutoDock Vina. Finally, a study of physicochemical properties, along with pharmacokinetic profiles, was carried out through SwissADME and ADMETlab 2.0 platforms. The promising results obtained with the molecules encoded as DB00549_BI_005, DB04868_BI_003, DB11984_BI_002, DB12364_BI_006 and DB12805_BI_004 must be confirmed by molecular dynamics studies, followed by in vitro and in vivo empirical tests that ratify the advocated in-silico results.
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Affiliation(s)
- João Ricardo Bueno de Morais Borba
- João Ricardo Bueno de Morais Borba, Laboratory of Molecular Modeling and Computer Simulation - MolMod-CS, Institute of Chemistry, Federal University of Alfenas - UNIFAL-MG, Alfenas, Brazil
| | - Leonardo Pereira de Araújo
- Leonardo Pereira de Araújo, Laboratory of Molecular Modeling and Computer Simulation - MolMod-CS, Institute of Chemistry, Federal University of Alfenas - UNIFAL-MG, Alfenas, Brazil
| | - Marcia Paranho Veloso
- Marcia Paranho Veloso, Laboratory of Molecular Modeling and Computer Simulation - MolMod-CS, Institute of Chemistry, Federal University of Alfenas - UNIFAL-MG, Alfenas, Brazil
| | - Nelson José Freitas da Silveira
- Nelson José Freitas da Silveira, Laboratory of Molecular Modeling and Computer Simulation - MolMod-CS, Institute of Chemistry, Federal University of Alfenas - UNIFAL-MG, Alfenas, Brazil
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5
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Afshinpour M, Smith LA, Chakravarty S. AQcalc: A web server that identifies weak molecular interactions in protein structures. Protein Sci 2023; 32:e4762. [PMID: 37596782 PMCID: PMC10503417 DOI: 10.1002/pro.4762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 07/25/2023] [Accepted: 08/15/2023] [Indexed: 08/20/2023]
Abstract
Weak molecular interactions play an important role in protein structure and function. Computational tools that identify weak molecular interactions are, therefore, valuable for the study of proteins. Here, we present AQcalc, a web server (https://aqcalcbiocomputing.com/) that can be used to identify anion-quadrupole (AQ) interactions, which are weak interactions involving aromatic residue (Trp, Tyr, and Phe) ring edges and anions (Asp, Glu, and phosphate ion) both within proteins and at their interfaces (protein-protein, protein-nucleic acids, and protein-lipid bilayer). AQcalc identifies AQ interactions as well as clusters involving AQ, cation-π, and salt bridges, among others. Utilizing AQcalc we analyzed weak interactions in protein models, even in the absence of experimental structures, to understand the contributions of weak interactions to deleterious structural changes, including those associated with oncogenic and germline disease variants. We identified several deleterious variants with disrupted AQ interactions (comparable in frequency to cation-π disruptions). Amyloid fibrils utilize AQ to bury anions at frequencies that far exceed those observed for globular proteins. AQ interactions were detected three and five times more frequently than the hydrogen-bonded AQ (HBAQ) in fibril structures and protein-lipid bilayer interfaces, respectively. By contrast, AQ and HBAQ interactions were detected with similar frequencies in globular proteins. Collectively, these findings suggest AQcalc will be effective in facilitating fine structural analysis. As other web utilities designed to identify protein residue interaction networks do not report AQ interactions, wide use of AQcalc will enrich our understanding of residue interaction networks and facilitate hypothesis testing by identifying and experimentally characterizing these comparably weak but important interactions.
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Affiliation(s)
- Maral Afshinpour
- Department of Chemistry & BiochemistrySouth Dakota State UniversityBrookingsSouth DakotaUSA
| | - Logan A. Smith
- Department of Chemistry & BiochemistrySouth Dakota State UniversityBrookingsSouth DakotaUSA
| | - Suvobrata Chakravarty
- Department of Chemistry & BiochemistrySouth Dakota State UniversityBrookingsSouth DakotaUSA
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6
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Yang JF, Wang F, Wang MY, Wang D, Zhou ZS, Hao GF, Li QX, Yang GF. CIPDB: A biological structure databank for studying cation and π interactions. Drug Discov Today 2023; 28:103546. [PMID: 36871844 DOI: 10.1016/j.drudis.2023.103546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/11/2023] [Accepted: 02/28/2023] [Indexed: 03/07/2023]
Abstract
As major forces for modulating protein folding and molecular recognition, cation and π interactions are extensively identified in protein structures. They are even more competitive than hydrogen bonds in molecular recognition, thus, are vital in numerous biological processes. In this review, we introduce the methods for the identification and quantification of cation and π interactions, provide insights into the characteristics of cation and π interactions in the natural state, and reveal their biological function together with our developed database (Cation and π Interaction in Protein Data Bank; CIPDB; http://chemyang.ccnu.edu.cn/ccb/database/CIPDB). This review lays the foundation for the in-depth study of cation and π interactions and will guide the use of molecular design for drug discovery.
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Affiliation(s)
- Jing-Fang Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Fan Wang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China
| | - Meng-Yao Wang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China
| | - Di Wang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China
| | - Zhong-Shi Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Ge-Fei Hao
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China; State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Research and Development Center for Fine Chemicals, Guizhou University, Guiyang 550025, PR China.
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China; International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan 430079, PR China; Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China.
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7
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Duque HM, Rodrigues G, Santos LS, Franco OL. The biological role of charge distribution in linear antimicrobial peptides. Expert Opin Drug Discov 2023; 18:287-302. [PMID: 36720196 DOI: 10.1080/17460441.2023.2173736] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Antimicrobial peptides (AMP) have received particular attention due to their capacity to kill bacteria. Although much is known about them, peptides are currently being further researched. A large number of AMPs have been discovered, but only a few have been approved for topical use, due to their promiscuity and other challenges, which need to be overcome. AREAS COVERED AMPs are diverse in structure. Consequently, they have varied action mechanisms when targeting microorganisms or eukaryotic cells. Herein, the authors focus on linear peptides, particularly those that are alpha-helical structured, and examine how their charge distribution and hydrophobic amino acids could modulate their biological activity. EXPERT OPINION The world currently needs urgent solutions to the infective problems caused by resistant pathogens. In order to start the race for antimicrobial development from the charge distribution viewpoint, bioinformatic tools will be necessary. Currently, there is no software available that allows to discriminate charge distribution in AMPs and predicts the biological effects of this event. Furthermore, there is no software available that predicts the side-chain length of residues and its role in biological functions. More specialized software is necessary.
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Affiliation(s)
- Harry Morales Duque
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160, Brasília-DF, Brazil
| | - Gisele Rodrigues
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160, Brasília-DF, Brazil
| | - Lucas Souza Santos
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160, Brasília-DF, Brazil
| | - Octávio Luiz Franco
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, PC: (CEP) 70.790-160, Brasília-DF, Brazil.,S-inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, PC: (CEP) 79117-010, Campo Grande-MS, Brazil
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8
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Innocent MT, Zhang Z, Cao R, Dai H, Zhang Y, Geng Y, Zhang Z, Jia G, Zhai M, Hu Z, Boland CS, Xiang H, Zhu M. Piezoresistive Fibers with Large Working Factors for Strain Sensing Applications. ACS APPLIED MATERIALS & INTERFACES 2023; 15:2277-2288. [PMID: 36576915 DOI: 10.1021/acsami.2c19830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Piezoresistive fibers with large working factors remain of great interest for strain sensing applications involving large strains, yet difficult to achieve. Here, we produced strain-sensitive fibers with large working factors by dip-coating nanocomposite piezoresistive inks on surface-modified polyether block amide (PEBA) fibers. Surface modification of neat PEBA fibers was carried out with polydopamine (PDA) while nanocomposite conductive inks consisted of styrene-ethylene-butylene-styrene (SEBS) elastomer and carbon black (CB). As such, the deposition of piezoresistive coatings was enabled through nonconventional hydrogen-bonding interactions. The resultant fibers demonstrated well-defined piezoresistive linear relationships, which increased with CB filler loading in SEBS. In addition, gauge factors decreased with increasing CB mass fractions from ∼15 to ∼7. Furthermore, we used the fatigue theory to predict the endurance limit (Ce) of our fibers toward resistance signal stability. Such a piezoresistive performance allowed us to explore the application of our fibers as strain sensors for monitoring the movement of finger joints.
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Affiliation(s)
- Mugaanire Tendo Innocent
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Ziling Zhang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Ran Cao
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Hongmei Dai
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Yuxuan Zhang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Yaqi Geng
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Zhihao Zhang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Guosheng Jia
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Mian Zhai
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Zexu Hu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Conor S Boland
- School of Mathematical and Physical Sciences, University of Sussex, BrightonBN19QH, U.K
| | - Hengxue Xiang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
| | - Meifang Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai201620, China
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9
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Jian J, Barkhatova D, Hammink R, Tinnemans P, Bickelhaupt FM, Poater J, Mecinović J. Through-Space Stabilization of an Imidazolium Cation by Aromatic Rings. J Org Chem 2022; 87:7875-7883. [PMID: 35653132 DOI: 10.1021/acs.joc.2c00533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Imidazole-based compounds are widely found in natural products, synthetic molecules, and biomolecules. Noncovalent interactions between the imidazole ring and other functional groups play an important role in determining the function of diverse molecules. However, there is a limited understanding of the underlying noncovalent interactions between imidazoles and aromatic systems. In this work, we report physical-organic chemistry studies on 2-(2,6-diarylphenyl)-1H-imidazoles and their protonated forms to investigate the noncovalent interactions between the central imidazole ring and two flanking aromatic rings possessing substituents at the para/meta position. Hammett analysis revealed that pKa values and proton affinities correlate well with Hammett σ values of para-substituents at the flanking rings. Additional quantitative Kohn-Sham molecular orbital and energy decomposition analyses reveal that through-space π-π interactions and NH-π interactions contribute to the intramolecular stabilization of the imidazolium cation. The results are important because they clearly demonstrate that the imidazolium cation forms energetically favorable noncovalent interactions with aromatic rings via the through-space effect, a knowledge that can be used in rational drug and catalyst design.
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Affiliation(s)
- Jie Jian
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Darina Barkhatova
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Roel Hammink
- Division of Immunotherapy, Oncode Institute, Radboud University Medical Center, Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands.,Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands
| | - Paul Tinnemans
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - F Matthias Bickelhaupt
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.,Department of Theoretical Chemistry, Amsterdam Center for Multiscale Modeling, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | - Jordi Poater
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain.,Departament de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Jasmin Mecinović
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
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10
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Al Mughram MH, Catalano C, Bowry JP, Safo MK, Scarsdale JN, Kellogg GE. 3D Interaction Homology: Hydropathic Analyses of the "π-Cation" and "π-π" Interaction Motifs in Phenylalanine, Tyrosine, and Tryptophan Residues. J Chem Inf Model 2021; 61:2937-2956. [PMID: 34101460 DOI: 10.1021/acs.jcim.1c00235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Three-dimensional (3D) maps of the hydropathic environments of protein amino acid residues are information-rich descriptors of preferred conformations, interaction types and energetics, and solvent accessibility. The interactions made by each residue are the primary factor for rotamer selection and the secondary, tertiary, and even quaternary protein structure. Our evolving basis set of environmental data for each residue type can be used to understand the protein structure. This work focuses on the aromatic residues phenylalanine, tyrosine, and tryptophan and their structural roles. We calculated and analyzed side chain-to-environment 3D maps for over 70,000 residues of these three types that reveal, with respect to hydrophobic and polar interactions, the environment around each. After binning with backbone ϕ/ψ and side chain χ1, we clustered each bin by 3D similarities between map-map pairs. For each of the three residue types, four bins were examined in detail: one in the β-pleat, two in the right-hand α-helix, and one in the left-hand α-helix regions of the Ramachandran plot. For high degrees of side chain burial, encapsulation of the side chain by hydrophobic interactions is ubiquitous. The more solvent-exposed side chains are more likely to be involved in polar interactions with their environments. Evidence for π-π interactions was observed in about half of the residues surveyed [phenylalanine (PHE): 53.3%, tyrosine (TYR): 34.1%, and tryptophan (TRP): 55.7%], but on an energy basis, this contributed to only ∼4% of the total. Evidence for π-cation interactions was observed in 14.1% of PHE, 8.3% of TYR, and 26.8% of TRP residues, but on an energy basis, this contributed to only ∼1%. This recognition of even these subtle interactions in the 3D hydropathic environment maps is key support for our interaction homology paradigm of protein structure elucidation and possibly prediction.
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Affiliation(s)
- Mohammed H Al Mughram
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298-0540, United States
| | - Claudio Catalano
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298-0540, United States
| | - John P Bowry
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284-2030, United States
| | - Martin K Safo
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298-0540, United States.,Institute of Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23298-0133, United States
| | - J Neel Scarsdale
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284-2030, United States.,Institute of Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23298-0133, United States
| | - Glen E Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23298-0540, United States.,Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284-2030, United States.,Institute of Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23298-0133, United States
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11
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Abstract
Phycobilisomes (PBSs) are extremely large chromophore-protein complexes on the stromal side of the thylakoid membrane in cyanobacteria and red algae. The main function of PBSs is light harvesting, and they serve as antennas and transfer the absorbed energy to the reaction centers of two photosynthetic systems (photosystems I and II). PBSs are composed of phycobiliproteins and linker proteins. How phycobiliproteins and linkers are organized in PBSs and how light energy is efficiently harvested and transferred in PBSs are the fundamental questions in the study of photosynthesis. In this review, the structures of the red algae Griffithsia pacifica and Porphyridium purpureum are discussed in detail, along with the functions of linker proteins in phycobiliprotein assembly and in fine-tuning the energy state of chromophores.
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Affiliation(s)
- Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology and Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China;
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12
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Mukherjee A, Saurabh S, Olive E, Jang YH, Lansac Y. Protamine Binding Site on DNA: Molecular Dynamics Simulations and Free Energy Calculations with Full Atomistic Details. J Phys Chem B 2021; 125:3032-3044. [DOI: 10.1021/acs.jpcb.0c09166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Arnab Mukherjee
- GREMAN, CNRS UMR 7347, Université de Tours, 37200 Tours, France
| | - Suman Saurabh
- GREMAN, CNRS UMR 7347, Université de Tours, 37200 Tours, France
| | - Enrick Olive
- GREMAN, CNRS UMR 7347, Université de Tours, 37200 Tours, France
| | - Yun Hee Jang
- Department of Energy Science and Engineering, DGIST, Daegu 42988, Korea
| | - Yves Lansac
- GREMAN, CNRS UMR 7347, Université de Tours, 37200 Tours, France
- Department of Energy Science and Engineering, DGIST, Daegu 42988, Korea
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Saclay, 91405 Orsay, France
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13
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Park S, Kim S, Jho Y, Hwang DS. Cation-π Interactions and Their Contribution to Mussel Underwater Adhesion Studied Using a Surface Forces Apparatus: A Mini-Review. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16002-16012. [PMID: 31423790 DOI: 10.1021/acs.langmuir.9b01976] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mussel underwater adhesion is a model phenomenon important for the understanding of broader biological adhesion and the development of biomimetic wet adhesives. The catechol moiety of 3,4-dihydroxyphenyl-l-alanine (DOPA) is known to be actively involved in the mechanism of mussel underwater adhesion; however, other underwater adhesion mechanisms are also crucial. The surface forces apparatus (SFA) has often been used to explore the contributions of other mechanisms to mussel underwater adhesion; e.g., recent SFA-based nanomechanical studies have revealed that cation-π interactions, one of the strongest intermolecular interactions in water, are the pivotal interactions of adhesive proteins involved in underwater mussel adhesion. This mini-review surveys recent research on cation-π interactions and their contributions to strong mussel underwater adhesion, shedding light on some biological processes and facilitating the development of biomedical adhesives.
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Affiliation(s)
- Sohee Park
- Division of Environmental Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Chengam-ro, Nam-gu , Pohang 37673 , Republic of Korea
| | - Sangsik Kim
- Division of Environmental Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Chengam-ro, Nam-gu , Pohang 37673 , Republic of Korea
- Division of Integrative Biosciences and Biotechnology , Pohang University of Science and Technology (POSTECH) , 77 Chengam-ro, Nam-gu , Pohang 37673 , Republic of Korea
| | - YongSeok Jho
- Department of Physics and Research Institute of Natural Science , Gyeongsang National University , Jinju 52828 , Republic of Korea
| | - Dong Soo Hwang
- Division of Environmental Science and Engineering , Pohang University of Science and Technology (POSTECH) , 77 Chengam-ro, Nam-gu , Pohang 37673 , Republic of Korea
- Division of Integrative Biosciences and Biotechnology , Pohang University of Science and Technology (POSTECH) , 77 Chengam-ro, Nam-gu , Pohang 37673 , Republic of Korea
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14
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Rajpurohit AS, Rajesh R, Muhamed RR, Jaccob M, Adaikala Baskar AJ, Kannappan V. DFT investigation of role of N - H⋯O and N - H⋯π interactions in the stabilization of the hydrogen bonded complexes of anisole with aromatic amines. Heliyon 2019; 5:e02155. [PMID: 31388586 PMCID: PMC6667824 DOI: 10.1016/j.heliyon.2019.e02155] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/17/2019] [Accepted: 07/22/2019] [Indexed: 11/18/2022] Open
Abstract
Theoretical investigations have been performed on hydrogen (H-) bonded complexes of two aromatic amines with anisole to investigate the effect of the methyl substituent on N – H⋯O and N – –H⋯π interactions. Natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) analyses were done to elucidate the nature of H- bonding. In 1:1 complexes, the total interaction energy of N-methylaniline complex is higher than that of aniline complex. The existence of bond critical point between N–H of amine and oxygen of anisole confirms weak hydrogen bonding. The energy decomposition analysis showed the role of CT in stabilizing complexes.
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Affiliation(s)
| | - R Rajesh
- Department of Physics, Sri Vijay Vidyalaya College of Arts and Science, Nallampalli, Dharmapuri, 636807, India
| | - R Raj Muhamed
- Department of Physics, Jamal Mohamed College, Tiruchirappalli, 621 004, India
| | - M Jaccob
- Department of Chemistry, Loyola College, Chennai 600 034, India
| | | | - V Kannappan
- Department of Chemistry, Presidency College, Chennai, 600 005, India
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15
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Ristić MM, Petković M, Milovanović B, Belić J, Etinski M. New hybrid cluster-continuum model for pKa values calculations: Case study of neurotransmitters’ amino group acidity. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2018.08.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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16
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Saranya V, Shankar R, Vijayakumar S. Structural exploration of viral matrix protein 40 interaction with the transition metal ions (Ag+ and Cu2+). J Biomol Struct Dyn 2018; 37:2875-2896. [DOI: 10.1080/07391102.2018.1498803] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- V. Saranya
- Department of Physics, Bharathiar University, Coimbatore, India
| | - R. Shankar
- Department of Physics, Bharathiar University, Coimbatore, India
| | - S. Vijayakumar
- Department of Medical Physics, Bharathiar University, Coimbatore, India
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17
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18
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Penque BA, Su L, Wang J, Ji W, Bale A, Luh F, Fulbright RK, Sarmast U, Sega AG, Konstantino M, Spencer-Manzon M, Pierce R, Yen Y, Lakhani SA. A homozygous variant in RRM2B is associated with severe metabolic acidosis and early neonatal death. Eur J Med Genet 2018; 62:103574. [PMID: 30439532 DOI: 10.1016/j.ejmg.2018.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 10/23/2018] [Accepted: 11/09/2018] [Indexed: 11/26/2022]
Abstract
RRM2B encodes the crucial p53-inducible ribonucleotide reductase small subunit 2 homolog (p53R2), which is required for DNA synthesis throughout the cell cycle. Mutations in this gene have been associated with a lethal mitochondrial depletion syndrome. Here we present the case of an infant with a novel homozygous p.Asn221Ser mutation in RRM2B who developed hypotonia, failure to thrive, sensorineural hearing loss, and severe metabolic lactic acidosis, ultimately progressing to death at 3 months of age. Through molecular modeling using the X-ray crystal structure of p53R2, we demonstrate that this mutation likely causes disruption of a highly conserved helix region of the protein by altering intramolecular interactions. This report expands our knowledge of potential pathogenic RRM2B mutations as well as our understanding of the molecular function of p53R2 and its role in the pathogenesis of mitochondrial DNA depletion.
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Affiliation(s)
- Brent A Penque
- Pediatric Genomics Discovery Program, Department of Pediatrics, Section of Critical Care Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Leila Su
- Department of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taipei, 110, Taiwan; Sino-American Cancer Foundation, Temple City, CA, USA
| | - Jianghai Wang
- Department of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taipei, 110, Taiwan; Sino-American Cancer Foundation, Temple City, CA, USA
| | - Weizhen Ji
- Pediatric Genomics Discovery Program, Department of Pediatrics, Section of Critical Care Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Allen Bale
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Frank Luh
- Department of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taipei, 110, Taiwan; Sino-American Cancer Foundation, Temple City, CA, USA
| | - Robert K Fulbright
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Uzair Sarmast
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT, USA
| | - Annalisa G Sega
- Pediatric Genomics Discovery Program, Department of Pediatrics, Section of Critical Care Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Monica Konstantino
- Pediatric Genomics Discovery Program, Department of Pediatrics, Section of Critical Care Medicine, Yale University School of Medicine, New Haven, CT, USA
| | | | - Richard Pierce
- Pediatric Genomics Discovery Program, Department of Pediatrics, Section of Critical Care Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Yun Yen
- Department of Cancer Biology and Drug Discovery, College of Medical Technology, Taipei Medical University, Taipei, 110, Taiwan; Sino-American Cancer Foundation, Temple City, CA, USA.
| | - Saquib A Lakhani
- Pediatric Genomics Discovery Program, Department of Pediatrics, Section of Critical Care Medicine, Yale University School of Medicine, New Haven, CT, USA.
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19
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Chakravarty S, Ung AR, Moore B, Shore J, Alshamrani M. A Comprehensive Analysis of Anion-Quadrupole Interactions in Protein Structures. Biochemistry 2018; 57:1852-1867. [PMID: 29482321 PMCID: PMC6051350 DOI: 10.1021/acs.biochem.7b01006] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The edgewise interactions of anions with phenylalanine (Phe) aromatic rings in proteins, known as anion-quadrupole interactions, have been well studied. However, the anion-quadrupole interactions of the tyrosine (Tyr) and tryptophan (Trp) rings have been less well studied, probably because these have been considered weaker than interactions of anions hydrogen bonded to Trp/Tyr side chains. Distinguishing such hydrogen bonding interactions, we comprehensively surveyed the edgewise interactions of certain anions (aspartate, glutamate, and phosphate) with Trp, Tyr, and Phe rings in high-resolution, nonredundant protein single chains and interfaces (protein-protein, DNA/RNA-protein, and membrane-protein). Trp/Tyr anion-quadrupole interactions are common, with Trp showing the highest propensity and average interaction energy for this type of interaction. The energy of an anion-quadrupole interaction (-15.0 to 0.0 kcal/mol, based on quantum mechanical calculations) depends not only on the interaction geometry but also on the ring atom. The phosphate anions at DNA/RNA-protein interfaces interact with aromatic residues with energies comparable to that of aspartate/glutamate anion-quadrupole interactions. At DNA-protein interfaces, the frequency of aromatic ring participation in anion-quadrupole interactions is comparable to that of positive charge participation in salt bridges, suggesting an underappreciated role for anion-quadrupole interactions at DNA-protein (or membrane-protein) interfaces. Although less frequent than salt bridges in single-chain proteins, we observed highly conserved anion-quadrupole interactions in the structures of remote homologues, and evolutionary covariance-based residue contact score predictions suggest that conserved anion-quadrupole interacting pairs, like salt bridges, contribute to polypeptide folding, stability, and recognition.
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Affiliation(s)
- Suvobrata Chakravarty
- Chemistry & Biochemistry, South Dakota State University, Brookings, SD, USA, 57007
- BioSNTR, Brookings, SD, USA, 57007
| | - Adron R. Ung
- Chemistry & Biochemistry, South Dakota State University, Brookings, SD, USA, 57007
| | - Brian Moore
- University Networking and Research Computing, South Dakota State University, Brookings, SD, USA, 57007
| | - Jay Shore
- Chemistry & Biochemistry, South Dakota State University, Brookings, SD, USA, 57007
| | - Mona Alshamrani
- Chemistry & Biochemistry, South Dakota State University, Brookings, SD, USA, 57007
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20
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Bootsma AN, Wheeler SE. Stacking Interactions of Heterocyclic Drug Fragments with Protein Amide Backbones. ChemMedChem 2018; 13:835-841. [PMID: 29451739 DOI: 10.1002/cmdc.201700721] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/18/2018] [Indexed: 12/25/2022]
Abstract
Stacking interactions can be important enthalpic contributors to drug binding. Among the less well-studied stacking interactions are those occurring between an arene and the π-face of an amide group. Given the ubiquity of heterocycles in drugs, combined with the abundance of amides in the protein backbone, optimizing these noncovalent interactions can provide a potential route to enhanced drug binding. Previously, Diederich et al. (ChemMedChem 2013, 8, 397-404) studied stacked dimers of a model amide with a set of 18 heterocycles, showing that computed interaction energies correlate with the dipole moments of the heterocycles and providing guidelines for the optimization of these interactions. We considered stacked dimers of the same model amide with a larger set of 28 heterocycles common in pharmaceuticals, by using more robust ab initio methods. While the overall trends in these new data corroborate many of the results of Diederich et al., these data provide a more refined view of the nature of amide stacking interactions. We present a robust scoring function for amide stacking interaction energies based on the molecular dipole moment and strength of the electric field above the arene.
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Affiliation(s)
- Andrea N Bootsma
- Center for Computational Quantum Chemistry, Department of Chemistry, University of Georgia, Athens, GA, 30602, USA.,Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA
| | - Steven E Wheeler
- Center for Computational Quantum Chemistry, Department of Chemistry, University of Georgia, Athens, GA, 30602, USA
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21
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Orabi EA, Lamoureux G. Cation-π Interactions between Quaternary Ammonium Ions and Amino Acid Aromatic Groups in Aqueous Solution. J Phys Chem B 2018; 122:2251-2260. [PMID: 29397727 DOI: 10.1021/acs.jpcb.7b11983] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cation-π interactions play important roles in the stabilization of protein structures and protein-ligand complexes. They contribute to the binding of quaternary ammonium ligands (mainly RNH3+ and RN(CH3)3+) to various protein receptors and are likely involved in the blockage of potassium channels by tetramethylammonium (TMA+) and tetraethylammonium (TEA+). Polarizable molecular models are calibrated for NH4+, TMA+, and TEA+ interacting with benzene, toluene, 4-methylphenol, and 3-methylindole (representing aromatic amino acid side chains) based on the ab initio MP2(full)/6-311++G(d,p) properties of the complexes. Whereas the gas-phase affinity of the ions with a given aromatic follows the trend NH4+ > TMA+ > TEA+, molecular dynamics simulations using the polarizable models show a reverse trend in water, likely due to a contribution from the hydrophobic effect. This reversed trend follows the solubility of aromatic hydrocarbons in quaternary ammonium salt solutions, which suggests a role for cation-π interactions in the salting-in of aromatic compounds in solution. Simulations in water show that the complexes possess binding free energies ranging from -1.3 to -3.3 kcal/mol (compared to gas-phase binding energies between -8.5 and -25.0 kcal/mol). Interestingly, whereas the most stable complexes involve TEA+ (the largest ion), the most stable solvent-separated complexes involve TMA+ (the intermediate-size ion).
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Affiliation(s)
- Esam A Orabi
- Department of Chemistry and Biochemistry and Centre for Research in Molecular Modeling (CERMM), Concordia University , 7141 Sherbrooke Street West, Montréal, Québec H4B 1R6, Canada
| | - Guillaume Lamoureux
- Department of Chemistry and Biochemistry and Centre for Research in Molecular Modeling (CERMM), Concordia University , 7141 Sherbrooke Street West, Montréal, Québec H4B 1R6, Canada
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22
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Zhang S, De Leon Rodriguez LM, Leung IKH, Cook GM, Harris PWR, Brimble MA. Total Synthesis and Conformational Study of Callyaerin A: Anti-Tubercular Cyclic Peptide Bearing a Rare Rigidifying (Z
)-2,3- Diaminoacrylamide Moiety. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712792] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Shengping Zhang
- School of Chemical Sciences; The University of Auckland; 23 Symonds St Auckland 1142 New Zealand
| | - Luis M. De Leon Rodriguez
- Maurice Wilkins Centre for Molecular Biodiscovery; The University of Auckland; Auckland 1142 New Zealand
| | - Ivanhoe K. H. Leung
- School of Chemical Sciences; The University of Auckland; 23 Symonds St Auckland 1142 New Zealand
| | - Gregory M. Cook
- Maurice Wilkins Centre for Molecular Biodiscovery; The University of Auckland; Auckland 1142 New Zealand
- Department of Microbiology and Immunology; University of Otago; Dunedin 9054 New Zealand
| | - Paul W. R. Harris
- School of Chemical Sciences; The University of Auckland; 23 Symonds St Auckland 1142 New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery; The University of Auckland; Auckland 1142 New Zealand
| | - Margaret A. Brimble
- School of Chemical Sciences; The University of Auckland; 23 Symonds St Auckland 1142 New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery; The University of Auckland; Auckland 1142 New Zealand
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23
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Zhang S, De Leon Rodriguez LM, Leung IKH, Cook GM, Harris PWR, Brimble MA. Total Synthesis and Conformational Study of Callyaerin A: Anti-Tubercular Cyclic Peptide Bearing a Rare Rigidifying (Z)-2,3- Diaminoacrylamide Moiety. Angew Chem Int Ed Engl 2018; 57:3631-3635. [PMID: 29345033 DOI: 10.1002/anie.201712792] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Indexed: 11/11/2022]
Abstract
The first synthesis of the anti-TB cyclic peptide callyaerin A (1), containing a rare (Z)-2,3-diaminoacrylamide bridging motif, is reported. Fmoc-formylglycine-diethylacetal was used as a masked equivalent of formylglycine in the synthesis of the linear precursor to 1. Intramolecular cyclization between the formylglycine residue and the N-terminal amine in the linear peptide precursor afforded the macrocyclic natural product 1. Synthetic 1 possessed potent anti-TB activity (MIC100 =32 μm) while its all-amide congener was inactive. Variable-temperature NMR studies of both the natural product and its all-amide analogue revealed the extraordinary rigidity imposed by this diaminoacrylamide unit on peptide conformation. The work reported herein pinpoints the intrinsic role that the (Z)-2,3-diaminoacrylamide moiety confers on peptide bioactivity.
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Affiliation(s)
- Shengping Zhang
- School of Chemical Sciences, The University of Auckland, 23 Symonds St, Auckland, 1142, New Zealand
| | - Luis M De Leon Rodriguez
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, 1142, New Zealand
| | - Ivanhoe K H Leung
- School of Chemical Sciences, The University of Auckland, 23 Symonds St, Auckland, 1142, New Zealand
| | - Gregory M Cook
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, 1142, New Zealand.,Department of Microbiology and Immunology, University of Otago, Dunedin, 9054, New Zealand
| | - Paul W R Harris
- School of Chemical Sciences, The University of Auckland, 23 Symonds St, Auckland, 1142, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, 1142, New Zealand
| | - Margaret A Brimble
- School of Chemical Sciences, The University of Auckland, 23 Symonds St, Auckland, 1142, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, 1142, New Zealand
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24
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Kumar K, Woo SM, Siu T, Cortopassi WA, Duarte F, Paton RS. Cation-π interactions in protein-ligand binding: theory and data-mining reveal different roles for lysine and arginine. Chem Sci 2018; 9:2655-2665. [PMID: 29719674 PMCID: PMC5903419 DOI: 10.1039/c7sc04905f] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/20/2018] [Indexed: 12/22/2022] Open
Abstract
The interactions of neutral aromatic ligands with cationic arginine, histidine and lysine amino acid residues have been studied with ab initio calculations, symmetry adapted perturbation theory (SAPT), and a systematic meta-analysis of X-ray structures.
We have studied the cation–π interactions of neutral aromatic ligands with the cationic amino acid residues arginine, histidine and lysine using ab initio calculations, symmetry adapted perturbation theory (SAPT), and a systematic meta-analysis of all available Protein Data Bank (PDB) X-ray structures. Quantum chemical potential energy surfaces (PES) for these interactions were obtained at the DLPNO-CCSD(T) level of theory and compared against the empirical distribution of 2012 unique protein–ligand cation–π interactions found in X-ray crystal structures. We created a workflow to extract these structures from the PDB, filtering by interaction type and residue pKa. The gas phase cation–π interaction of lysine is the strongest by more than 10 kcal mol–1, but the empirical distribution of 582 X-ray structures lies away from the minimum on the interaction PES. In contrast, 1381 structures involving arginine match the underlying calculated PES with good agreement. SAPT analysis revealed that underlying differences in the balance of electrostatic and dispersion contributions are responsible for this behavior in the context of the protein environment. The lysine–arene interaction, dominated by electrostatics, is greatly weakened by a surrounding dielectric medium and causes it to become essentially negligible in strength and without a well-defined equilibrium separation. The arginine–arene interaction involves a near equal mix of dispersion and electrostatic attraction, which is weakened to a much smaller degree by the surrounding medium. Our results account for the paucity of cation–π interactions involving lysine, even though this is a more common residue than arginine. Aromatic ligands are most likely to interact with cationic arginine residues as this interaction is stronger than for lysine in higher polarity surroundings.
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Affiliation(s)
- Kiran Kumar
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , UK .
| | - Shin M Woo
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , UK .
| | - Thomas Siu
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , UK .
| | - Wilian A Cortopassi
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , UK .
| | - Fernanda Duarte
- EaStCHEM School of Chemistry , University of Edinburgh , Joseph Black Building, David Brewster Road , Edinburgh EH9 3FJ , UK .
| | - Robert S Paton
- Chemistry Research Laboratory , University of Oxford , 12 Mansfield Road , Oxford OX1 3TA , UK .
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25
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Ieritano C, Featherstone J, Carr PJJ, Marta RA, Loire E, McMahon TB, Hopkins WS. The structures and properties of anionic tryptophan complexes. Phys Chem Chem Phys 2018; 20:26532-26541. [DOI: 10.1039/c8cp04533j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
IRMPD spectroscopy and electronic structure calculations are employed to identify π–π interactions in ionic tryptophan clusters.
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Affiliation(s)
| | | | | | - Rick A. Marta
- Department of Chemistry, University of Waterloo
- Waterloo
- Canada
| | - Estelle Loire
- Laboratoire Chimie Physique – CLIO, Bâtiment 201, Porte 2, Campus Universitaire d’Orsay
- France
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26
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Shen M, Dong W, Qian J, Zou L. Antimicrobial activity and membrane interaction mechanism of the antimicrobial peptides derived from Rana chensinensis with short sequences. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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27
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Ferreira de Freitas R, Schapira M. A systematic analysis of atomic protein-ligand interactions in the PDB. MEDCHEMCOMM 2017; 8:1970-1981. [PMID: 29308120 PMCID: PMC5708362 DOI: 10.1039/c7md00381a] [Citation(s) in RCA: 232] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/15/2017] [Indexed: 12/20/2022]
Abstract
As the protein databank (PDB) recently passed the cap of 123 456 structures, it stands more than ever as an important resource not only to analyze structural features of specific biological systems, but also to study the prevalence of structural patterns observed in a large body of unrelated structures, that may reflect rules governing protein folding or molecular recognition. Here, we compiled a list of 11 016 unique structures of small-molecule ligands bound to proteins - 6444 of which have experimental binding affinity - representing 750 873 protein-ligand atomic interactions, and analyzed the frequency, geometry and impact of each interaction type. We find that hydrophobic interactions are generally enriched in high-efficiency ligands, but polar interactions are over-represented in fragment inhibitors. While most observations extracted from the PDB will be familiar to seasoned medicinal chemists, less expected findings, such as the high number of C-H···O hydrogen bonds or the relatively frequent amide-π stacking between the backbone amide of proteins and aromatic rings of ligands, uncover underused ligand design strategies.
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Affiliation(s)
| | - Matthieu Schapira
- Structural Genomics Consortium , University of Toronto , Toronto , ON M5G 1L7 , Canada .
- Department of Pharmacology and Toxicology , University of Toronto , Toronto , ON M5S 1A8 , Canada
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28
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Bearne SL, St Maurice M. A Paradigm for CH Bond Cleavage: Structural and Functional Aspects of Transition State Stabilization by Mandelate Racemase. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2017; 109:113-160. [PMID: 28683916 DOI: 10.1016/bs.apcsb.2017.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mandelate racemase (MR) from Pseudomonas putida catalyzes the Mg2+-dependent, 1,1-proton transfer reaction that racemizes (R)- and (S)-mandelate. MR shares a partial reaction (i.e., the metal ion-assisted, Brønsted base-catalyzed proton abstraction of the α-proton of carboxylic acid substrates) and structural features ((β/α)7β-barrel and N-terminal α + β capping domains) with a vast group of homologous, yet functionally diverse, enzymes in the enolase superfamily. Mechanistic and structural studies have developed this enzyme into a paradigm for understanding how enzymes such as those of the enolase superfamily overcome kinetic and thermodynamic barriers to catalyze the abstraction of an α-proton from a carbon acid substrate with a relatively high pKa value. Structural studies on MR bound to intermediate/transition state analogues have delineated those structural features that MR uses to stabilize transition states and enhance reaction rates of proton abstraction. Kinetic, site-directed mutagenesis, and structural studies have also revealed that the phenyl ring of the substrate migrates through the hydrophobic cavity within the active site during catalysis and that the Brønsted acid-base catalysts (Lys 166 and His 297) may be utilized as binding determinants for inhibitor recognition. In addition, structural studies on the adduct formed from the irreversible inhibition of MR by 3-hydroxypyruvate revealed that MR can form and deprotonate a Schiff-base with 3-hydroxypyruvate to yield an enol(ate)-aldehyde adduct, suggesting a possible evolutionary link between MR and the Schiff-base forming aldolases. As the archetype of the enolase superfamily, mechanistic and structural studies on MR will continue to enhance our understanding of enzyme catalysis and furnish insights into the evolution of enzyme function.
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Radhika R, Shankar R, Vijayakumar S, Kolandaivel P. Role of 6-Mercaptopurine in the potential therapeutic targets DNA base pairs and G-quadruplex DNA: insights from quantum chemical and molecular dynamics simulations. J Biomol Struct Dyn 2017; 36:1369-1401. [PMID: 28436311 DOI: 10.1080/07391102.2017.1323013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The theoretical studies on DNA with the anticancer drug 6-Mercaptopurine (6-MP) are investigated using theoretical methods to shed light on drug designing. Among the DNA base pairs considered, 6-MP is stacked with GC with the highest interaction energy of -46.19 kcal/mol. Structural parameters revealed that structure of the DNA base pairs is deviated from the planarity of the equilibrium position due to the formation of hydrogen bonds and stacking interactions with 6-MP. These deviations are verified through the systematic comparison between X-H bond contraction and elongation and the associated blue shift and red shift values by both NBO analysis and vibrational analysis. Bent's rule is verified for the C-H bond contraction in the 6-MP interacted base pairs. The AIM results disclose that the higher values of electron density (ρ) and Laplacian of electron density (∇2ρ) indicate the increased overlap between the orbitals that represent the strong interaction and positive values of the total electron density show the closed-shell interaction. The relative sensitivity of the chemical shift values for the DNA base pairs with 6-MP is investigated to confirm the hydrogen bond strength. Molecular dynamics simulation studies of G-quadruplex DNA d(TGGGGT)4 with 6-MP revealed that the incorporation of 6-MP appears to cause local distortions and destabilize the G-quadruplex DNA.
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Affiliation(s)
- R Radhika
- a Department of Physics , Bharathiar University , Coimbatore , India
| | - R Shankar
- a Department of Physics , Bharathiar University , Coimbatore , India
| | - S Vijayakumar
- b Department of Medical Physics , Bharathiar University , Coimbatore , India
| | - P Kolandaivel
- a Department of Physics , Bharathiar University , Coimbatore , India
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Kumar R, Gaurav A, Pal S, Kumar KR, Sridhar B, Tewari AK. Reverse Intramolecular Stacking in o-Xylene Bridge Symmetrical Dimers of 2-Thiopyridine Derivative: Assessment of the Conformational Stability. ChemistrySelect 2017. [DOI: 10.1002/slct.201700269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ranjeet Kumar
- Department of Chemistry (Centre of Advanced Studies); Institute of Science; Banaras Hindu University; Varanasi 221005 India
| | - Archana Gaurav
- Department of Chemistry (Centre of Advanced Studies); Institute of Science; Banaras Hindu University; Varanasi 221005 India
| | - Shiv Pal
- Indian Institute of Science Education and Research, Pune; Dr. Homi Bhabha Road, Pashan Pune 411008 India
| | - Krishnan R. Kumar
- Laboratory of X-ray Crystallography; Indian Institute of Chemical Technology; Hyderabad 500 607 India
| | - Balasubramanian Sridhar
- Laboratory of X-ray Crystallography; Indian Institute of Chemical Technology; Hyderabad 500 607 India
| | - Ashish K. Tewari
- Department of Chemistry (Centre of Advanced Studies); Institute of Science; Banaras Hindu University; Varanasi 221005 India
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31
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Kumar S, Singh SK, Vaishnav JK, Hill JG, Das A. Interplay among Electrostatic, Dispersion, and Steric Interactions: Spectroscopy and Quantum Chemical Calculations of π-Hydrogen Bonded Complexes. Chemphyschem 2017; 18:828-838. [PMID: 28124829 DOI: 10.1002/cphc.201601405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/24/2017] [Indexed: 11/07/2022]
Abstract
π-Hydrogen bonding interactions are ubiquitous in both materials and biology. Despite their relatively weak nature, great progress has been made in their investigation by experimental and theoretical methods, but this becomes significantly more complicated when secondary intermolecular interactions are present. In this study, the effect of successive methyl substitution on the supramolecular structure and interaction energy of indole⋅⋅⋅methylated benzene (ind⋅⋅⋅n-mb, n=1-6) complexes is probed through a combination of supersonic jet experiments and benchmark-quality quantum chemical calculations. It is demonstrated that additional secondary interactions introduce a subtle interplay among electrostatic and dispersion forces, as well as steric repulsion, which fine-tunes the overall structural motif. Resonant two-photon ionization and IR-UV double-resonance spectroscopy techniques are used to probe jet-cooled ind⋅⋅⋅n-mb (n=2, 3, 6) complexes, with redshifting of the N-H IR stretching frequency showing that increasing the degree of methyl substitution increases the strength of the primary N-H⋅⋅⋅π interaction. Ab initio harmonic frequency and binding energy calculations confirm this trend for all six complexes. Electronic spectra of the three dimers are broad and structureless, with quantum chemical calculations revealing that this is likely to be due to multiple tilted conformations of each dimer possessing similar stabilization energies.
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Affiliation(s)
- Sumit Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune, 411008, Maharashtra, India.,Present address: Department of Dynamics at Surfaces, Max Planck Institute of Biophysical Chemistry, Am Faßberg 11, 37077, Gottingen, Germany
| | - Santosh K Singh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune, 411008, Maharashtra, India
| | - Jamuna K Vaishnav
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune, 411008, Maharashtra, India.,Present address: Indian Institute of Technology (IIT) Indore, Khandwa Rd, Simrol, Madhya, Pradesh, 452020, India
| | - J Grant Hill
- Department of Chemistry, University of Sheffield, Sheffield, S3 7HF, UK
| | - Aloke Das
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune, 411008, Maharashtra, India
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Chiang CH, Fu YH, Horng JC. Formation of AAB-Type Collagen Heterotrimers from Designed Cationic and Aromatic Collagen-Mimetic Peptides: Evaluation of the C-Terminal Cation−π Interactions. Biomacromolecules 2017; 18:985-993. [DOI: 10.1021/acs.biomac.6b01838] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Chu-Harn Chiang
- Department of Chemistry and ‡Frontier Research Center on Fundamental and Applied
Science of Matters, National Tsing Hua University, 101 Sec. 2 Kuang-Fu Rd., Hsinchu, Taiwan 30013, ROC
| | - Yi-Hsuan Fu
- Department of Chemistry and ‡Frontier Research Center on Fundamental and Applied
Science of Matters, National Tsing Hua University, 101 Sec. 2 Kuang-Fu Rd., Hsinchu, Taiwan 30013, ROC
| | - Jia-Cherng Horng
- Department of Chemistry and ‡Frontier Research Center on Fundamental and Applied
Science of Matters, National Tsing Hua University, 101 Sec. 2 Kuang-Fu Rd., Hsinchu, Taiwan 30013, ROC
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Antimicrobial and anti-inflammatory activities of three chensinin-1 peptides containing mutation of glycine and histidine residues. Sci Rep 2017; 7:40228. [PMID: 28054660 PMCID: PMC5215317 DOI: 10.1038/srep40228] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/01/2016] [Indexed: 11/16/2022] Open
Abstract
The natural peptide chensinin-1 doesnot exhibit its desired biological properties. In this study, the mutant MC1-1 was designed by replacing Gly in the chensinin-1 sequence with Trp. Mutants MC1-2 and MC1-3 were designed based on the MC1-1 sequence to investigate the specific role of His residues. The mutated peptides presented α-helicity in a membrane-mimetic environment and exhibited broad-spectrum antimicrobial activities; in contrast to Trp residues, His residues were dispensable for interacting with the cell membrane. The interactions between the mutant peptides and lipopolysaccharide (LPS) facilitated the ingestion of peptides by Gram-negative bacteria. The binding affinities of the peptides were similar, at approximately 10 μM, but ΔH for MC1-2 was −7.3 kcal.mol−1, which was 6-9 folds higher than those of MC1-1 and MC1-3, probably due to the conformational changes. All mutant peptides demonstrated the ability to inhibit LPS-induced tumour-necrosis factor-α (TNF-α) and interleukin-6 (IL-6) release from murine RAW264.7 cells. In addition, the representative peptide MC1-1showed better inhibition of serum TNF-α and IL-6 levels compared to polymyxin B (PMB), a potent binder and neutralizer of LPS as positive control in LPS-challenged mice model. These data suggest that the mutant peptides could be promising molecules for development as chensinin-based therapeutic agents against sepsis.
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Elucidating a chemical defense mechanism of Antarctic sponges: A computational study. J Mol Graph Model 2016; 71:104-115. [PMID: 27894019 DOI: 10.1016/j.jmgm.2016.11.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/21/2016] [Accepted: 11/06/2016] [Indexed: 11/22/2022]
Abstract
In 2000, a novel secondary metabolite (erebusinone, Ereb) was isolated from the Antarctic sea sponge, Isodictya erinacea. The bioactivity of Ereb was investigated, and it was found to inhibit molting when fed to the arthropod species Orchomene plebs. Xanthurenic acid (XA) is a known endogenous molt regulator present in arthropods. Experimental studies have confirmed that XA inhibits molting by binding to either (or both) of two P450 enzymes (CYP315a1 or CYP314a1) that are responsible for the final two hydroxylations in the production of the molt-inducing hormone, 20-hydroxyecdysone (20E). The lack of crystal structures and biochemical assays for CYP315a1 or CYP314a1, has prevented further experimental exploration of XA and Ereb's molt inhibition mechanisms. Herein, a wide array of computational techniques - homology modeling, molecular dynamics simulations, binding site bioinformatics, flexible receptor-flexible ligand docking, and molecular mechanics-generalized Born surface area calculations - have been employed to elucidate the structure-function relationships between the aforementioned P450s and the two described small molecule inhibitors (Ereb and XA). Results indicate that Ereb likely targets CYP315a1 by interacting with a network of aromatic residues in the binding site, while XA may inhibit both CYP315a1 and CYP314a1 because of its aromatic, as well as charged nature.
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Jia S, Yang Z, Ren K, Tian Z, Dong C, Ma R, Yu G, Yang W. Removal of antibiotics from water in the coexistence of suspended particles and natural organic matters using amino-acid-modified-chitosan flocculants: A combined experimental and theoretical study. JOURNAL OF HAZARDOUS MATERIALS 2016; 317:593-601. [PMID: 27348257 DOI: 10.1016/j.jhazmat.2016.06.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/26/2016] [Accepted: 06/10/2016] [Indexed: 05/10/2023]
Abstract
Contamination of trace antibiotics is widely found in surface water sources. This work delineates removal of trace antibiotics (norfloxacin (NOR), sulfadiazine (SDZ) or tylosin (TYL)) from synthetic surface water by flocculation, in the coexistence of inorganic suspended particles (kaolin) and natural organic matter (humic acid, HA). To avoid extra pollution caused by petrochemical products-based modification reagents, environmental-friendly amino-acid-modified-chitosan flocculants, Ctrp and Ctyr, with different functional aromatic-rings structures were employed. Jar tests at various pHs exhibited that, Ctyr, owning phenol groups as electron donors, was favored for elimination of cationic NOR (∼50% removal; optimal pH: 6; optimal dosage: 4mg/L) and TYL (∼60% removal; optimal pH: 7; optimal dosage: 7.5mg/L), due to π-π electron donator-acceptor (EDA) effect and unconventional H-bonds. Differently, Ctrp with indole groups as electron acceptor had better removal rate (∼50%) of SDZ anions (electron donator). According to correlation analysis, the coexisted kaolin and HA played positive roles in antibiotics' removal. Detailed pairwise interactions in molecular level among different components were clarified by spectral analysis and theoretical calculations (density functional theory), which are important for both the structural design of new flocculants aiming at targeted contaminants and understanding the environmental behaviors of antibiotics in water.
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Affiliation(s)
- Shuying Jia
- School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, PR China
| | - Zhen Yang
- School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, PR China.
| | - Kexin Ren
- School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, PR China
| | - Ziqi Tian
- Department of Chemistry, University of California, Riverside, CA 92521, United States
| | - Chang Dong
- School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, PR China
| | - Ruixue Ma
- School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, PR China
| | - Ge Yu
- School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, PR China
| | - Weiben Yang
- School of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, Nanjing 210023, PR China.
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37
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Petasis-Ugi ligands: New affinity tools for the enrichment of phosphorylated peptides. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1031:86-93. [DOI: 10.1016/j.jchromb.2016.07.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/15/2016] [Accepted: 07/18/2016] [Indexed: 01/07/2023]
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38
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Calvanese L, Falcigno L, D'Auria G. Essential dynamics analysis captures the concerted motion of the integrin-binding site in jerdostatin, an RTS disintegrin. Biopolymers 2016; 103:158-66. [PMID: 25363370 DOI: 10.1002/bip.22578] [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: 06/27/2014] [Revised: 10/16/2014] [Accepted: 10/20/2014] [Indexed: 11/09/2022]
Abstract
Disintegrins, small molecular weight proteins contained in the venom of vipers and rattlesnakes, are high-affinity and selectivity integrin antagonists. Disintegrins inhibitory epitope mainly consists in a tripeptide sequence localized in a mobile loop protruding from the protein core. RTS and/or KTS tripeptide characterizes the most recently discovered group of disintegrins that selectively block α1β1 integrin receptor. A NMR study dedicated to structure and dynamics properties of jerdostatin, an RTS disintegrin, demonstrated that the substitution of the native RTS with KTS motif impaired flexibility and inhibitory activity of the molecule. Here we add atomic details to the experimental profiles of jerdostatin and its R24K mutant by analyzing the dynamics behavior of the molecules through computational methods. For jerdostatin wild type, molecular dynamics simulations and essential dynamics analyses showed that Y31 residue acts as hinge element in the concerted motions involving the active loop and the C-terminal tail. R24 side chain ability to engage both cation-π and H-bond interactions with Y31 residue was found crucial for that breathing mechanism. Less significant loop-tail concerted motions were observed for the R24K mutant. The description at atomic resolution of jerdostatin dynamics is useful for decoding the influence of specific residues on disintegrin functional properties.
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Reddy GR, Avadhani AS, Rajaram S. Activation of Benzyl Aryl Carbonates: The Role of Cation-π Interactions. J Org Chem 2016; 81:4134-41. [PMID: 27158833 DOI: 10.1021/acs.joc.6b00441] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Benzyl aryl carbonates can react with a nucleophile to yield an activated electrophile and an aryloxide anion. Previously, we had utilized this in the synthesis of α-nitro esters from nitroalkanes. To further understand the process of activation of these carbonates by nucleophiles, we have performed kinetic studies on the hydrolysis of carbonates using nucleophiles. Rate constants for the hydrolysis were obtained under pseudo-first-order conditions with DABCO as the nucleophile. A comparison of rate constant for hydrolysis of isobutyl phenyl carbonate with benzyl phenyl carbonate shows that the presence of benzyl group results in a 16-fold acceleration of hydrolysis rate. This indicates that the transition state for activation of carbonate is stabilized by cation-π interactions. A comparison of the rate constant for various aromatic rings indicates that electron-donating substituents on the benzyl groups accelerate the rate of hydrolysis. Studies were also carried out with DMAP as nucleophile and the results are presented. Our studies show that stable carbonates can be activated using nucleophiles. Activated acyl groups generated from acid anhydrides have been used in several enantioselective reactions. Our studies show that carbonates can be stable alternatives to acid anhydrides.
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Affiliation(s)
- Golipalli Ramana Reddy
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur P.O., Bangalore 560064, India
| | - Anusha S Avadhani
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur P.O., Bangalore 560064, India
| | - Sridhar Rajaram
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur P.O., Bangalore 560064, India
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40
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Singh SK, Das A. The n → π* interaction: a rapidly emerging non-covalent interaction. Phys Chem Chem Phys 2016; 17:9596-612. [PMID: 25776003 DOI: 10.1039/c4cp05536e] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This perspective describes the current status of a recently discovered non-covalent interaction named as the n → π* interaction, which is very weak and counterintuitive in nature. In this review, we have provided a brief overview of the widespread presence of this interaction in biomacromolecules, small biomolecules and materials, as well as the physical nature of this interaction explored using various experimental and theoretical techniques. It has been found that this interaction is equally important to other non-covalent interactions for the stability and specific structures of biomolecules and materials. An in-depth understanding of this interaction can help in designing more efficient functional materials as well as drugs. The review also provides a future outlook in terms of exploring the detailed functional role of this interaction in biological processes and its direct spectroscopic evidence, which other commonly known non-covalent interactions (conventional hydrogen bonding, π-hydrogen bonding, π-stacking, etc.) have.
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Affiliation(s)
- Santosh K Singh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune-411008, Maharashtra, India.
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Yusuf M, Mohamed N, Mohamad S, Janezic D, Damodaran KV, Wahab HA. H274Y’s Effect on Oseltamivir Resistance: What Happens Before the Drug Enters the Binding Site. J Chem Inf Model 2016; 56:82-100. [DOI: 10.1021/acs.jcim.5b00331] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Muhammad Yusuf
- Pharmaceutical
Design and Simulation (PhDS) Laboratory, School of Pharmaceutical
Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
| | - Nornisah Mohamed
- Pharmaceutical
Design and Simulation (PhDS) Laboratory, School of Pharmaceutical
Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
| | - Suriyati Mohamad
- Pharmaceutical
Design and Simulation (PhDS) Laboratory, School of Pharmaceutical
Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
- School
of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
| | - Dusanka Janezic
- Faculty
of Mathematics, Natural Sciences and Information Technologies, University of Primorska, SI-6000 Koper, Slovenia
| | - K. V. Damodaran
- Pharmaceutical
Design and Simulation (PhDS) Laboratory, School of Pharmaceutical
Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
| | - Habibah A. Wahab
- Pharmaceutical
Design and Simulation (PhDS) Laboratory, School of Pharmaceutical
Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia
- Malaysian
Institute of Pharmaceuticals and Nutraceuticals, Ministry of Science, Technology and Innovation, Halaman Bukit Gambir, 11900 Bayan Lepas, Pulau Pinang, Malaysia
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Cauët E, Rooman M, Wintjens R, Liévin J, Biot C. Histidine-Aromatic Interactions in Proteins and Protein-Ligand Complexes: Quantum Chemical Study of X-ray and Model Structures. J Chem Theory Comput 2015; 1:472-83. [PMID: 26641514 DOI: 10.1021/ct049875k] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
His-aromatic complexes, with the His located above the aromatic plane, are stabilized by π-π, δ(+)-π and/or cation-π interactions according to whether the His is neutral or protonated and the partners are in stacked or T-shape conformations. Here we attempt to probe the relative strength of these interactions as a function of the geometry and protonation state, in gas phase, in water and protein-like environments (acetone, THF and CCl4), by means of quantum chemistry calculations performed up to second order of the Møller-Plesset pertubation theory. Two sets of conformations are considered for that purpose. The first set contains 89 interactions between His and Phe, Tyr, Trp, or Ade, observed in X-ray structures of proteins and protein-ligand complexes. The second set contains model structures obtained by moving an imidazolium/imidazole moiety above a benzene ring or an adenine moiety. We found that the protonated complexes are much more stable than the neutral ones in gas phase. This higher stability is due to the electrostatic contributions, the electron correlation contributions being equally important in the two forms. Thus, π-π and δ(+)-π interactions present essentially favorable electron correlation energy terms, whereas cation-π interactions feature in addition favorable electrostatic energies. The protonated complexes remain more stable than the neutral ones in protein-like environments, but the difference is drastically reduced. Furthermore, the T-shape conformation is undoubtedly more favorable than the stacked one in gas phase. This advantage decreases in the solvents, and the stacked conformation becomes even slightly more favorable in water. The frequent occurrence of His-aromatic interactions in catalytic sites, at protein-DNA or protein-ligand interfaces and in 3D domain swapping proteins emphasize their importance in biological processes.
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Affiliation(s)
- Emilie Cauët
- Service de Chimie quantique et Photophysique, Université Libre de Bruxelles, CP 160/09, 50 Avenue F.D. Roosevelt, B-1050 Bruxelles, Belgium, Unité de Bioinformatique génomique et structurale, Université Libre de Bruxelles, CP 165/61, 50 Avenue F.D. Roosevelt, Institut de Pharmacie, B-1050 Bruxelles, Belgium, and Service de Chimie générale, Université Libre de Bruxelles, CP 206/04, Bld du Triomphe, B-1050 Bruxelles, Belgium
| | - Marianne Rooman
- Service de Chimie quantique et Photophysique, Université Libre de Bruxelles, CP 160/09, 50 Avenue F.D. Roosevelt, B-1050 Bruxelles, Belgium, Unité de Bioinformatique génomique et structurale, Université Libre de Bruxelles, CP 165/61, 50 Avenue F.D. Roosevelt, Institut de Pharmacie, B-1050 Bruxelles, Belgium, and Service de Chimie générale, Université Libre de Bruxelles, CP 206/04, Bld du Triomphe, B-1050 Bruxelles, Belgium
| | - René Wintjens
- Service de Chimie quantique et Photophysique, Université Libre de Bruxelles, CP 160/09, 50 Avenue F.D. Roosevelt, B-1050 Bruxelles, Belgium, Unité de Bioinformatique génomique et structurale, Université Libre de Bruxelles, CP 165/61, 50 Avenue F.D. Roosevelt, Institut de Pharmacie, B-1050 Bruxelles, Belgium, and Service de Chimie générale, Université Libre de Bruxelles, CP 206/04, Bld du Triomphe, B-1050 Bruxelles, Belgium
| | - Jacques Liévin
- Service de Chimie quantique et Photophysique, Université Libre de Bruxelles, CP 160/09, 50 Avenue F.D. Roosevelt, B-1050 Bruxelles, Belgium, Unité de Bioinformatique génomique et structurale, Université Libre de Bruxelles, CP 165/61, 50 Avenue F.D. Roosevelt, Institut de Pharmacie, B-1050 Bruxelles, Belgium, and Service de Chimie générale, Université Libre de Bruxelles, CP 206/04, Bld du Triomphe, B-1050 Bruxelles, Belgium
| | - Christophe Biot
- Service de Chimie quantique et Photophysique, Université Libre de Bruxelles, CP 160/09, 50 Avenue F.D. Roosevelt, B-1050 Bruxelles, Belgium, Unité de Bioinformatique génomique et structurale, Université Libre de Bruxelles, CP 165/61, 50 Avenue F.D. Roosevelt, Institut de Pharmacie, B-1050 Bruxelles, Belgium, and Service de Chimie générale, Université Libre de Bruxelles, CP 206/04, Bld du Triomphe, B-1050 Bruxelles, Belgium
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Abstract
UV photodissociation (UVPD) action spectroscopy is reported to provide a sensitive tool for the detection of radical sites in gas-phase peptide ions. UVPD action spectra of peptide cation radicals of the z-type generated by electron-transfer dissociation point to the presence of multiple structures formed as a result of spontaneous isomerizations by hydrogen atom migration. N-terminal Cα radicals are identified as the dominant components, but the content of isomers differing in the radical defect position in the backbone or side chain depends on the nature of the aromatic residue with phenylalanine being more prone to isomerization than tryptophan. These results illustrate that spontaneous hydrogen atom migrations can occur in peptide cation-radicals upon electron-transfer dissociation.
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Affiliation(s)
- Huong T H Nguyen
- Department of Chemistry, University of Washington , Bagley Hall, Box 351700, Seattle, Washington 981195-1700, United States
| | - Christopher J Shaffer
- Department of Chemistry, University of Washington , Bagley Hall, Box 351700, Seattle, Washington 981195-1700, United States
| | - Robert Pepin
- Department of Chemistry, University of Washington , Bagley Hall, Box 351700, Seattle, Washington 981195-1700, United States
| | - František Tureček
- Department of Chemistry, University of Washington , Bagley Hall, Box 351700, Seattle, Washington 981195-1700, United States
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Nandy B, Saurabh S, Sahoo AK, Dixit NM, Maiti PK. The SPL7013 dendrimer destabilizes the HIV-1 gp120-CD4 complex. NANOSCALE 2015; 7:18628-18641. [PMID: 26495445 DOI: 10.1039/c5nr04632g] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The poly (l-lysine)-based SPL7013 dendrimer with naphthalene disulphonate surface groups blocks the entry of HIV-1 into target cells and is in clinical trials for development as a topical microbicide. Its mechanism of action against R5 HIV-1, the HIV-1 variant implicated in transmission across individuals, remains poorly understood. Using docking and fully atomistic MD simulations, we find that SPL7013 binds tightly to R5 gp120 in the gp120-CD4 complex but weakly to gp120 alone. Further, the binding, although to multiple regions of gp120, does not occlude the CD4 binding site on gp120, suggesting that SPL7013 does not prevent the binding of R5 gp120 to CD4. Using MD simulations to compute binding energies of several docked structures, we find that SPL7013 binding to gp120 significantly weakens the gp120-CD4 complex. Finally, we use steered molecular dynamics (SMD) to study the kinetics of the dissociation of the gp120-CD4 complex in the absence of the dendrimer and with the dendrimer bound in each of the several stable configurations to gp120. We find that SPL7013 significantly lowers the force required to rupture the gp120-CD4 complex and accelerates its dissociation. Taken together, our findings suggest that SPL7013 compromises the stability of the R5 gp120-CD4 complex, potentially preventing the accrual of the requisite number of gp120-CD4 complexes across the virus-cell interface, thereby blocking virus entry.
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Affiliation(s)
- Bidisha Nandy
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India.
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Nagar M, Bearne SL. An additional role for the Brønsted acid-base catalysts of mandelate racemase in transition state stabilization. Biochemistry 2015; 54:6743-52. [PMID: 26480244 DOI: 10.1021/acs.biochem.5b00982] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mandelate racemase (MR) catalyzes the interconversion of the enantiomers of mandelate and serves as a paradigm for understanding the enzyme-catalyzed abstraction of an α-proton from a carbon acid substrate with a high pKa. The enzyme utilizes a two-base mechanism with Lys 166 and His 297 acting as Brønsted acid and base catalysts, respectively, in the R → S reaction direction. In the S → R reaction direction, their roles are reversed. Using isothermal titration calorimetry (ITC), MR is shown to bind the intermediate/transition state (TS) analogue inhibitor benzohydroxamate (BzH) in an entropy-driven process with a value of ΔCp equal to -358 ± 3 cal mol(-1) K(-1), consistent with an increased number of hydrophobic interactions. However, MR binds BzH with an affinity that is ∼2 orders of magnitude greater than that predicted solely on the basis of hydrophobic interactions [St. Maurice, M., and Bearne, S. L. (2004) Biochemistry 43, 2524], suggesting that additional specific interactions contribute to binding. To test the hypothesis that cation-π/NH-π interactions between the side chains of Lys 166 and His 297 and the aromatic ring and/or the hydroxamate/hydroximate moiety of BzH contribute to the binding of BzH, site-directed mutagenesis was used to generate the MR variants K166M, K166C, H297N, and K166M/H297N and their binding affinity for various ligands determined using ITC. Comparison of the binding affinities of these MR variants with the intermediate/TS analogues BzH and cyclohexanecarbohydroxamate revealed that cation-π/NH-π interactions between His 297 and the hydroxamate/hydroximate moiety and the phenyl ring of BzH contribute approximately 0.26 and 0.91 kcal/mol to binding, respectively, while interactions with Lys 166 contribute approximately 1.74 and 1.74 kcal/mol, respectively. Similarly, comparison of the binding affinities of these mutants with substrate analogues revealed that Lys 166 contributes >2.93 kcal/mol to the binding of (R)-atrolactate, and His 297 contributes 2.46 kcal/mol to the binding of (S)-atrolactate. These results are consistent with Lys 166 and His 297 playing dual roles in catalysis: they act as Brønsted acid-base catalysts, and they stabilize both the enolate moiety and phenyl ring of the altered substrate in the TS.
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Affiliation(s)
- Mitesh Nagar
- Department of Biochemistry and Molecular Biology, Dalhousie University , Halifax, NS B3H 4R2, Canada
| | - Stephen L Bearne
- Department of Biochemistry and Molecular Biology, Dalhousie University , Halifax, NS B3H 4R2, Canada.,Department of Chemistry, Dalhousie University , Halifax, NS B3H 4R2, Canada
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Bandyopadhyay D, Bhanja K, Mohan S, Ghosh SK, Choudhury N. Effects of Concentration on Like-Charge Pairing of Guanidinium Ions and on the Structure of Water: An All-Atom Molecular Dynamics Simulation Study. J Phys Chem B 2015; 119:11262-74. [DOI: 10.1021/acs.jpcb.5b03064] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dibyendu Bandyopadhyay
- Heavy Water Division and ‡Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - K. Bhanja
- Heavy Water Division and ‡Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Sadhana Mohan
- Heavy Water Division and ‡Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Swapan K. Ghosh
- Heavy Water Division and ‡Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Niharendu Choudhury
- Heavy Water Division and ‡Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
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Mucić ID, Nikolić MR, Stojanović SĐ. Contribution of cation-π interactions to the stability of Sm/LSm oligomeric assemblies. PROTOPLASMA 2015; 252:947-958. [PMID: 25408427 DOI: 10.1007/s00709-014-0727-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/30/2014] [Indexed: 06/04/2023]
Abstract
In this work, we have analyzed the influence of cation-π interactions to the stability of Sm/LSm assemblies and their environmental preferences. The number of interactions formed by arginine is higher than lysine in the cationic group, while histidine is comparatively higher than phenylalanine and tyrosine in the π group. Arg-Tyr interactions are predominant among the various pairs analyzed. The furcation level of multiple cation-π interactions is much higher than that of single cation-π interactions in Sm/LSm interfaces. We have found hot spot residues forming cation-π interactions, and hot spot composition is similar for all aromatic residues. The Arg-Phe pair has the strongest interaction energy of -8.81 kcal mol(-1) among all the possible pairs of amino acids. The extent of burial of the residue side-chain correlates with the ΔΔG of binding for residues in the core and also for hot spot residues cation-π bonded across the interface. Secondary structure of the cation-π residues shows that Arg and Lys preferred to be in strand. Among the π residues, His prefers to be in helix, Phe prefers to be in turn, and Tyr prefers to be in strand. Stabilization centers for these proteins showed that all the five residues found in cation-π interactions are important in locating one or more of such centers. More than 50 % of the cation-π interacting residues are highly conserved. It is likely that the cation-π interactions contribute significantly to the overall stability of Sm/LSm proteins.
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Affiliation(s)
- Ivana D Mucić
- Faculty of Chemistry, University of Belgrade, Belgrade, Serbia
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Wei C, Pohorille A. M2 proton channel: toward a model of a primitive proton pump. ORIGINS LIFE EVOL B 2015; 45:241-8. [PMID: 25777465 DOI: 10.1007/s11084-015-9421-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/06/2014] [Indexed: 01/23/2023]
Abstract
Transmembrane proton transfer was essential to early cellular systems in order to transduce energy for metabolic functions. The reliable, efficient and controlled generation of proton gradients became possible only with the emergence of active proton pumps. On the basis of features shared by most modern proton pumps we identify the essential mechanistic steps in active proton transport. Further, we discuss the mechanism of action of a small, transmembrane M2 proton channel from influenza A virus as a model for proton transport in protocells. The M2 channel is a 94-residue long, α-helical tetramer that is activated at low pH and exhibits high selectivity and directionality. A shorter construct, built of transmembrane fragments that are only 24 amino acids in length, exhibits very similar proton transport properties. Molecular dynamics simulations on the microsecond time-scale carried out for the M2 channel provided atomic level details on the activation of the channel in response to protonation of the histidine residue, His37. The pathway of proton conduction is mediated by His37, which accepts and donates protons at different interconverting conformation states when pH is lower than 6.5. The Val27 and Trp41 gates and the salt bridge between Asp44 and Arg45 further enhance the directionality of proton transport. It is argued that the architecture and the mechanism of action similar to that found in the M2 channel might have been the perfect starting point for evolution towards the earliest proton pumps, indicating that active proton transport could have readily emerged from simple, passive proton channels.
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Affiliation(s)
- Chenyu Wei
- NASA Ames Research Center, Mail Stop 239-4, Moffett Field, CA, 94035, USA
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Trujillo C, Rodriguez-Sanz AA, Rozas I. Aromatic Amino Acids-Guanidinium Complexes through Cation-π Interactions. Molecules 2015; 20:9214-28. [PMID: 26007180 PMCID: PMC6272432 DOI: 10.3390/molecules20059214] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 01/11/2023] Open
Abstract
Continuing with our interest in the guanidinium group and the different interactions than can establish, we have carried out a theoretical study of the complexes formed by this cation and the aromatic amino acids (phenylalanine, histidine, tryptophan and tyrosine) using DFT methods and PCM-water solvation. Both hydrogen bonds and cation-π interactions have been found upon complexation. These interactions have been characterized by means of the analysis of the molecular electron density using the Atoms-in-Molecules approach as well as the orbital interactions using the Natural Bond Orbital methodology. Finally, the effect that the cation-π and hydrogen bond interactions exert on the aromaticity of the corresponding amino acids has been evaluated by calculating the theoretical NICS values, finding that the aromatic character was not heavily modified upon complexation.
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Affiliation(s)
- Cristina Trujillo
- Trinity Biomedical Sciences Institute, School of Chemistry, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
| | - Ana A Rodriguez-Sanz
- Departamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, Campus de Lugo, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain.
| | - Isabel Rozas
- Trinity Biomedical Sciences Institute, School of Chemistry, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
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Singh SK, Kumar S, Das A. Competition between n → π(Ar)* and conventional hydrogen bonding (N-H···N) interactions: an ab initio study of the complexes of 7-azaindole and fluorosubstituted pyridines. Phys Chem Chem Phys 2015; 16:8819-27. [PMID: 24326976 DOI: 10.1039/c3cp54169j] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we have investigated a subtle competition between a very weak n → π(Ar)* interaction and a very strong hydrogen bond (N-H···N) interaction present in the complexes of 7-azaindole with a series of 2,6-substituted fluoropyridines and observed how the weak interaction modulates the overall structural motif of these complexes in the presence of the strong interaction. We have studied the structures and binding energies of these complexes using MP2 as well as dispersion-corrected DFT calculations. It has been found that the strength of the N-H···N interaction in these complexes decreases with increasing fluorination in the fluoropyridine ring while the proximity between the nitrogen atom in 7-azaindole and the aromatic ring of fluoropyridine increases through n → π(Ar)* interaction. Comparison of the binding energy values as well as structural parameters of these complexes calculated at the B3LYP level with those obtained at the MP2, M05-2X, and B97-D levels of theory clearly indicates that the dispersion effect is mostly responsible for this attractive n → π(Ar)* interaction. This conclusion is also supported by localized molecular orbital-energy decomposition analysis (LMO-EDA). The current investigation is the first theoretical study on the n → π(Ar)* interaction in the presence of a conventional strong hydrogen bonding interaction in the molecular system. Thus the present study has great significance for understanding the structures of the biomolecules as well as materials, as these interactions are very often present there simultaneously.
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Affiliation(s)
- Santosh K Singh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr Homi Bhabha Road, Pune-411008, Maharashtra, India.
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