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Zhu M, Wang L, Zhang H, Fan S, Wang Z, Li QX, Wang Y, Liu S. Interactions between tetrahydroisoindoline-1,3-dione derivatives and human serum albumin via multiple spectroscopy techniques. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:17735-17748. [PMID: 29671232 DOI: 10.1007/s11356-018-1955-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 04/04/2018] [Indexed: 06/08/2023]
Abstract
Some tetrahydroisoindoline-1,3-dione derivatives (TDDs) possess potent herbicidal activity. To assess possible impacts of TDDs on humans, the interactions between TDDs and human serum albumin (HSA) were evaluated with steady-state and time-resolved fluorescence spectroscopy, synchronous fluorescence spectroscopy, Fourier transform-infrared spectroscopy, and circular dichroism spectroscopy. The thermodynamic data obtained at temperatures of 298, 307, and 316 K indicate that TDDs spontaneously bind to HSA and thus form a TDD-HSA complex. The conformation and secondary structure of HSA are changed, and the intrinsic fluorescence of HSA is statically quenched by TDDs. Moreover, the TDD-HSA complex is formed primarily through electrostatic interactions and has only one binding site on HSA. A competitive ligand-binding assay revealed that site II (subdomain IIIA) displays the greatest affinity for TDDs. In addition, an acute toxicity bioassay showed no zebrafish mortality upon exposure to 4000 μg L-1 of TDDs. This work is helpful for understanding interactions between TDDs and HSA.
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Affiliation(s)
- Meiqing Zhu
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei, 230036, China
| | - Lijun Wang
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei, 230036, China
| | - Hao Zhang
- Department of Applied Chemistry, College of Science, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing, 100193, China
| | - Shisuo Fan
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei, 230036, China
| | - Zhen Wang
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei, 230036, China
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, 96822, USA
| | - Yi Wang
- Key Laboratory of Agri-food Safety of Anhui Province, College of Resources and Environment, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei, 230036, China.
- Department of Applied Chemistry, College of Science, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing, 100193, China.
| | - Shangzhong Liu
- Department of Applied Chemistry, College of Science, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing, 100193, China.
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Bhandari YR, Chapagain PP, Gerstman BS. Lattice model simulations of the effects of the position of a peptide trigger segment on helix folding and dimerization. J Chem Phys 2012; 137:105103. [DOI: 10.1063/1.4752247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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3
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Abstract
Protein aggregation is believed to be responsible for a number of human diseases and limits the yields of pharmaceutical proteins during production. Computer simulations can be used to develop novel experimentally testable hypotheses pertaining to aggregation. While all-atom simulations with explicit solvent are too computationally intensive to address the multitude of relevant time scales, coarse-grained models make it possible to observe the transition of monomers to an equilibrium containing aggregates. Here, we provide the reader with background information and a list of steps for setting up, performing, and analyzing computer simulations of aggregating coarse-grained (CG) proteins.
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Affiliation(s)
- Troy Cellmer
- Laboratory of Chemical Physics, National Institute of Digestive and Diabetes and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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Chapagain PP, Liu Y, Gerstman BS. The trigger sequence in the GCN4 leucine zipper: α-helical propensity and multistate dynamics of folding and dimerization. J Chem Phys 2008; 129:175103. [DOI: 10.1063/1.3006421] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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5
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In silico protein fragmentation reveals the importance of critical nuclei on domain reassembly. Biophys J 2007; 94:1575-88. [PMID: 17993485 DOI: 10.1529/biophysj.107.119651] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein complementation assays (PCAs) based on split protein fragments have become powerful tools that facilitate the study and engineering of intracellular protein-protein interactions. These assays are based on the observation that a given protein can be split into two inactive fragments and these fragments can reassemble into the original properly folded and functional structure. However, one experimentally observed limitation of PCA systems is that the folding of a protein from its fragments is dramatically slower relative to that of the unsplit parent protein. This is due in part to a poor understanding of how PCA design parameters such as split site position in the primary sequence and size of the resulting fragments contribute to the efficiency of protein reassembly. We used a minimalist on-lattice model to analyze how the dynamics of the reassembly process for two model proteins was affected by the location of the split site. Our results demonstrate that the balanced distribution of the "folding nucleus," a subset of residues that are critical to the formation of the transition state leading to productive folding, between protein fragments is key to their reassembly.
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Young TM, Roberts CJ. A quasichemical approach for protein-cluster free energies in dilute solution. J Chem Phys 2007; 127:165101. [DOI: 10.1063/1.2779323] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Cellmer T, Bratko D, Prausnitz JM, Blanch HW. Protein aggregation in silico. Trends Biotechnol 2007; 25:254-61. [PMID: 17433843 PMCID: PMC2680282 DOI: 10.1016/j.tibtech.2007.03.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2006] [Revised: 02/22/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
Protein aggregation is a challenge to the successful manufacture of protein therapeutics; it can impose severe limitations on purification yields and compromise formulation stability. Advances in computer power, and the wealth of computational studies pertaining to protein folding, have facilitated the development of molecular simulation as a tool to investigate protein misfolding and aggregation. Here, we highlight the successes of protein aggregation studies carried out in silico, with a particular emphasis on studies related to biotechnology. To conclude, we discuss future prospects for the field, and identify several biotechnology-related problems that would benefit from molecular simulation.
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Affiliation(s)
- Troy Cellmer
- National Institutes of Health, Bethesda, MD 20892, USA
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Chen Y, Zhang Q, Ding J. A coarse-grained model for the formation of α helix with a noninteger period on simple cubic lattices. J Chem Phys 2006; 124:184903. [PMID: 16709135 DOI: 10.1063/1.2196878] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Periodicity is an important parameter in the characterization of a helix in proteins. In this work, a coarse-grained model for a homopolypeptide in simple cubic lattices has been extended to build an alpha helix with a noninteger period. The lattice model is based on the bond fluctuation algorithm in which bond lengths and orientations are altered in a quasicontinuous way, and the simulation is performed via dynamic Monte Carlo simulation. Hydrogen bonds are assumed to be formed between a virtual-carbonyl group in a residue and a downstream virtual-imino group in another residue. Consequently, the period of the formed alpha helix is a noninteger. An improved spatial correlation function has been suggested to quantitatively describe the periodicity of the helical conformation, by which helical period and helical persistent length can be calculated by statistics. The resultant periods are very close to 3.6 residues; the persistent length based upon the improved definition can be larger or smaller than the chain length and reflect the inherent regularity of a chain including one or multiple helical blocks. The simulation outputs agree with the calculation of the Zimm-Bragg theory based upon the associated nucleation parameter and propagation parameter as well.
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Affiliation(s)
- Yantao Chen
- Key Laboratory of Molecular Engineering of Polymers of Chinese Ministry of Education, Department of Macromolecular Science, Fudan University, Shanghai 200433, China
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Costello G, Euston SR. A Monte Carlo Simulation of the Aggregation, Phase-Separation, and Gelation of Model Globular Molecules. J Phys Chem B 2006; 110:10151-64. [PMID: 16706477 DOI: 10.1021/jp056304v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Monte Carlo computer simulation on a square 3-D lattice is used to model state behavior of globular copolymers. Two types of globular molecules were defined. One consisted of a single type of subunit (a homopolymer) while the second contained a core of strongly attractive subunits and an outer layer of less strongly attractive subunits (a heteropolymer). Systems of globules were simulated at varied volume fraction (V(F)) and reduced temperature (T(R)), and state diagrams were constructed. These state diagrams contained state boundaries defined by the V(F)/T(R) combinations at which the system formed a percolating network and at which the various component subunits in the globule unfolded. Simulated systems could exist in a number of states (between 4 and 7), depending on the V(F), T(R), whether the molecule was a homo- or heteroglobule and whether the globules were allowed to interact with each other or not. All systems exhibited a gelation/crossover line that resembled a lower critical solution temperature. All systems also exhibited a critical gelation concentration, above which a continuous network was formed. The critical gelation concentration varied between about 2-4% V(F) depending on the type of system. This is comparable to experimental critical gelation concentrations of in the region of 4% (w/w) for a range of associating polymers and biopolymers such as globular proteins and polysaccharides. Other states were formed which included one where elongated, fibril-like aggregated strands were formed, and a micelle-like aggregated state. The results are discussed in terms of the known state behavior of associating polymers and biopolymers (proteins and polysaccharides).
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Affiliation(s)
- Geoffrey Costello
- School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, UK
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Bratko D, Cellmer T, Prausnitz JM, Blanch HW. Effect of single-point sequence alterations on the aggregation propensity of a model protein. J Am Chem Soc 2006; 128:1683-91. [PMID: 16448142 DOI: 10.1021/ja056837h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sequences of contemporary proteins are believed to have evolved through a process that optimized their overall fitness, including their resistance to deleterious aggregation. Biotechnological processing may expose therapeutic proteins to conditions that are much more conducive to aggregation than those encountered in a cellular environment. An important task of protein engineering is to identify alternative sequences that would protect proteins when processed at high concentrations without altering their native structure associated with specific biological function. Our computational studies exploit parallel tempering simulations of coarse-grained model proteins to demonstrate that isolated amino acid residue substitutions can result in significant changes in the aggregation resistance of the protein in a crowded environment while retaining protein structure in isolation. A thermodynamic analysis of protein clusters subject to competing processes of folding and association shows that moderate mutations can produce effects similar to those caused by changes in system conditions, including temperature, concentration, and solvent composition, that affect the aggregation propensity. The range of conditions where a protein can resist aggregation can therefore be tuned by sequence alterations, although the protein generally may retain its generic ability for aggregation.
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Affiliation(s)
- Dusan Bratko
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, USA.
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Bratko D, Cellmer T, Prausnitz JM, Blanch HW. Molecular simulation of protein aggregation. Biotechnol Bioeng 2006; 96:1-8. [PMID: 17136749 DOI: 10.1002/bit.21232] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Computer simulation offers unique possibilities for investigating molecular-level phenomena difficult to probe experimentally. Drawing from a wealth of studies concerning protein folding, computational studies of protein aggregation are emerging. These studies have been successful in capturing aspects of aggregation known from experiment and are being used to refine experimental methods aimed at abating aggregation. Here we review molecular-simulation studies of protein aggregation conducted in our laboratory. Specific attention is devoted to issues with implications for biotechnology.
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Affiliation(s)
- Dusan Bratko
- Department of Chemistry, Virginia Commonwealth University, Richmond, VA 23284, USA
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12
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Grover A, Dugar D, Kundu B. Predicting alternate structure attainment and amyloidogenesis: a nonlinear signal analysis approach. Biochem Biophys Res Commun 2005; 338:1410-6. [PMID: 16263079 DOI: 10.1016/j.bbrc.2005.10.104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Accepted: 10/07/2005] [Indexed: 11/20/2022]
Abstract
Chain hydrophobicity values have been used in prediction of alternate structure attainment by a polypeptide. Nonlinear signal analysis on the hydrophobicity values gives important clues about the propensities of particular stretches of a protein to form local or nonlocal contacts. These contacts determine the folding behavior of a polypeptide and helps in predicting the final structure that can be attained. A nonlinear signal analysis called the recurrent quantification analysis has been carried out using the hydrophobicity values on a wide range of proteins obtained from human, plant, and fungal sources. Here, we show that such an analysis gives us an easy handle in determining sequences within the proteins that may be important in beta-sheet formation leading to amyloidosis.
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Affiliation(s)
- Abhinav Grover
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
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Cellmer T, Bratko D, Prausnitz JM, Blanch H. Protein-folding landscapes in multichain systems. Proc Natl Acad Sci U S A 2005; 102:11692-7. [PMID: 16081531 PMCID: PMC1188005 DOI: 10.1073/pnas.0505342102] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Computational studies of proteins have significantly improved our understanding of protein folding. These studies are normally carried out by using chains in isolation. However, in many systems of practical interest, proteins fold in the presence of other molecules. To obtain insight into folding in such situations, we compare the thermodynamics of folding for a Miyazawa-Jernigan model 64-mer in isolation to results obtained in the presence of additional chains. The melting temperature falls as the chain concentration increases. In multichain systems, free-energy landscapes for folding show an increased preference for misfolded states. Misfolding is accompanied by an increase in interprotein interactions; however, near the folding temperature, the transition from folded chains to misfolded and associated chains is entropically driven. A majority of the most probable interprotein contacts are also native contacts, suggesting that native topology plays a role in early stages of aggregation.
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Affiliation(s)
- Troy Cellmer
- Department of Chemical Engineering, University of California, Berkeley, CA 94720, USA
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