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Chen H, Siu SWI, Wong CTT, Qiu J, Cheung AKK, Lee SMY. Anti-epileptic Kunitz-like peptides discovered in the branching coral Acropora digitifera through transcriptomic analysis. Arch Toxicol 2022; 96:2589-2608. [PMID: 35604417 DOI: 10.1007/s00204-022-03311-4] [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: 02/24/2022] [Accepted: 04/27/2022] [Indexed: 11/29/2022]
Abstract
Approximately 50 million people are suffering from epilepsy worldwide. Corals have been used for treating epilepsy in traditional Chinese medicine, but the mechanism of this treatment is unknown. In this study, we analyzed the transcriptome of the branching coral Acropora digitifera and obtained its Kyoto Encyclopedia of Genes and Genomes (KEGG), EuKaryotic Orthologous Groups (KOG) and Gene Ontology (GO) annotation. Combined with multiple sequence alignment and phylogenetic analysis, we discovered three polypeptides, we named them AdKuz1, AdKuz2 and AdKuz3, from A. digitifera that showed a close relationship to Kunitz-type peptides. Molecular docking and molecular dynamics simulation indicated that AdKuz1 to 3 could interact with GABAA receptor but AdKuz2-GABAA remained more stable than others. The biological experiments showed that AdKuz1 and AdKuz2 exhibited an anti-inflammatory effect by decreasing the aberrant level of nitric oxide (NO), IL-6, TNF-α and IL-1β induced by LPS in BV-2 cells. In addition, the pentylenetetrazol (PTZ)-induced epileptic effect on zebrafish was remarkably suppressed by AdKuz1 and AdKuz2. AdKuz2 particularly showed superior anti-epileptic effects compared to the other two peptides. Furthermore, AdKuz2 significantly decreased the expression of c-fos and npas4a, which were up-regulated by PTZ treatment. In addition, AdKuz2 reduced the synthesis of glutamate and enhanced the biosynthesis of gamma-aminobutyric acid (GABA). In conclusion, the results indicated that AdKuz2 may affect the synthesis of glutamate and GABA and enhance the activity of the GABAA receptor to inhibit the symptoms of epilepsy. We believe, AdKuz2 could be a promising anti-epileptic agent and its mechanism of action should be further investigated.
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Affiliation(s)
- Hanbin Chen
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, China.,Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China
| | - Shirley Weng In Siu
- Institute of Science and Environment, University of Saint Joseph, Macao, China
| | - Clarence Tsun Ting Wong
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jianwen Qiu
- Department of Biology and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Hong Kong Baptist University, Hong Kong, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Alex Kwok-Kuen Cheung
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Simon Ming Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, China. .,Department of Pharmaceutical Sciences, Faculty of Health Sciences, University of Macau, Macao, China.
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Explanation of Structure and Function of kv1.3 Potent Blocker From Mesobuthus eupeus Venom Gland: A New Promise in Drug Development. Jundishapur J Nat Pharm Prod 2022. [DOI: 10.5812/jjnpp.120271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Scorpions and other venomous animals are sought with great concern because venom is a source of novel peptides with exciting features. Some toxins of scorpion venom are effectors of potassium channels. Previous studies strongly support the importance of potassium channel toxins for use as pharmacological tools or potential drugs. Objectives: Here, a three-dimensional (3-D) structure and function of a potent acidic blocker of the human voltage-gated potassium ion channel, Kv1.3, previously identified in the scorpion Mesobuthus eupeus venom gland, were interpreted. Methods: The 3-D structure of meuK2-2 was generated using homology modeling. The interaction of meuK2-2 with the Kv1.3 channel was evaluated using a computational protocol employing peptide-protein docking experiments, pose clustering, and 100 ns molecular dynamic simulations to make the 3-D models of the meuK2-2/Kv1.3 complex trustworthy. Results: A CSα/β (cysteine-stabilized α-helical and β-sheet) fold was found for the 3-D structure of meuK2-2. In a different mechanism from what was identified so far, meuK2-2 binds to both turret and pore loop of Kv1.3 through two key residues (Ala28 and Ser11) and H-bonds. The binding of meuK2-2 induces some conformational changes to Kv1.3. Eventually, the side chain of a positively charged amino acid (His9) occupies the channel's pore. All together blocks the ion permeation pathway. Conclusions: MeuK2-2 could block Kv1.3 by a new mechanism. So, it could be a unique target for further investigations to develop a pharmacological tool and potential drug.
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Zhao Y, Chen Z, Cao Z, Li W, Wu Y. Diverse Structural Features of Potassium Channels Characterized by Scorpion Toxins as Molecular Probes. Molecules 2019; 24:molecules24112045. [PMID: 31146335 PMCID: PMC6600638 DOI: 10.3390/molecules24112045] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/15/2019] [Accepted: 05/26/2019] [Indexed: 12/21/2022] Open
Abstract
Scorpion toxins are well-known as the largest potassium channel peptide blocker family. They have been successfully proven to be valuable molecular probes for structural research on diverse potassium channels. The potassium channel pore region, including the turret and filter regions, is the binding interface for scorpion toxins, and structural features from different potassium channels have been identified using different scorpion toxins. According to the spatial orientation of channel turrets with differential sequence lengths and identities, conformational changes and molecular surface properties, the potassium channel turrets can be divided into the following three states: open state with less hindering effects on toxin binding, half-open state or half-closed state with certain effects on toxin binding, and closed state with remarkable effects on toxin binding. In this review, we summarized the diverse structural features of potassium channels explored using scorpion toxin tools and discuss future work in the field of scorpion toxin-potassium channel interactions.
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Affiliation(s)
- Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zongyun Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China.
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
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4
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Semenyuk P, Muronetz V. Protein Interaction with Charged Macromolecules: From Model Polymers to Unfolded Proteins and Post-Translational Modifications. Int J Mol Sci 2019; 20:E1252. [PMID: 30871103 PMCID: PMC6429204 DOI: 10.3390/ijms20051252] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 12/18/2022] Open
Abstract
Interaction of proteins with charged macromolecules is involved in many processes in cells. Firstly, there are many naturally occurred charged polymers such as DNA and RNA, polyphosphates, sulfated glycosaminoglycans, etc., as well as pronouncedly charged proteins such as histones or actin. Electrostatic interactions are also important for "generic" proteins, which are not generally considered as polyanions or polycations. Finally, protein behavior can be altered due to post-translational modifications such as phosphorylation, sulfation, and glycation, which change a local charge of the protein region. Herein we review molecular modeling for the investigation of such interactions, from model polyanions and polycations to unfolded proteins. We will show that electrostatic interactions are ubiquitous, and molecular dynamics simulations provide an outstanding opportunity to look inside binding and reveal the contribution of electrostatic interactions. Since a molecular dynamics simulation is only a model, we will comprehensively consider its relationship with the experimental data.
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Affiliation(s)
- Pavel Semenyuk
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia.
| | - Vladimir Muronetz
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia.
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia.
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5
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Tobassum S, Tahir HM, Arshad M, Zahid MT, Ali S, Ahsan MM. Nature and applications of scorpion venom: an overview. TOXIN REV 2018. [DOI: 10.1080/15569543.2018.1530681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Saadia Tobassum
- Department of Zoology, Government College University, Lahore, Pakistan
| | | | - Muhammad Arshad
- Department of Zoology, University of Education Lower Mall Campus, Lahore, Pakistan
| | | | - Shaukat Ali
- Department of Zoology, Government College University, Lahore, Pakistan
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Zhang Y, Zhao Y, Liu H, Yu W, Yang F, Li W, Cao Z, Wu Y. Mouse β-Defensin 3, A Defensin Inhibitor of Both Its Endogenous and Exogenous Potassium Channels. Molecules 2018; 23:molecules23061489. [PMID: 29925780 PMCID: PMC6099957 DOI: 10.3390/molecules23061489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 06/09/2018] [Accepted: 06/11/2018] [Indexed: 12/03/2022] Open
Abstract
The human defensins are recently discovered to inhibit potassium channels, which are classical targets of the animal toxins. Whether other vertebrate defensins are potassium channel inhibitors remains unknown. In this work, we reported that the mouse β-defensin 3 (mBD3) was a novel inhibitor of both endogenous and exogenous potassium channels. The structural analysis showed that mBD3 is the most identical to human Kv1.3 channel-sensitive human β-defensin 2 (hBD2). However, the pharmacological profiles indicated that the recombinant mBD3 (rmBD3) weakly inhibited the mouse and human Kv1.3 channels. Different from the pharmacological features of human β-defensins, mBD3 more selectively inhibited the mouse Kv1.6 and human KCNQ1/KCNE1 channels with IC50 values of 0.6 ± 0.4 μM and 1.2 ± 0.8 μM, respectively. The site directed mutagenesis experiments indicated that the extracellular pore region of mouse Kv1.6 channel was the interaction site of rmBD3. In addition, the minor effect on the channel conductance-voltage relationship curves implied that mBD3 might bind the extracellular transmembrane helices S1-S2 linker and/or S3-S4 linker of mouse Kv1.6 channel. Together, these findings not only revealed mBD3 as a novel inhibitor of both endogenous and exogenous potassium channels, but also provided a clue to investigate the role of mBD3-Kv1.6 channel interaction in the physiological and pathological field in the future.
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Affiliation(s)
- Yaoyun Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Hongyue Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Weiwei Yu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Fan Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Wenhua Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
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7
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Yuan S, Gao B, Zhu S. Molecular Dynamics Simulation Reveals Specific Interaction Sites between Scorpion Toxins and K v1.2 Channel: Implications for Design of Highly Selective Drugs. Toxins (Basel) 2017; 9:toxins9110354. [PMID: 29104247 PMCID: PMC5705969 DOI: 10.3390/toxins9110354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/15/2017] [Accepted: 10/19/2017] [Indexed: 01/06/2023] Open
Abstract
The Kv1.2 channel plays an important role in the maintenance of resting membrane potential and the regulation of the cellular excitability of neurons, whose silencing or mutations can elicit neuropathic pain or neurological diseases (e.g., epilepsy and ataxia). Scorpion venom contains a variety of peptide toxins targeting the pore region of this channel. Despite a large amount of structural and functional data currently available, their detailed interaction modes are poorly understood. In this work, we choose four Kv1.2-targeted scorpion toxins (Margatoxin, Agitoxin-2, OsK-1, and Mesomartoxin) to construct their complexes with Kv1.2 based on the experimental structure of ChTx-Kv1.2. Molecular dynamics simulation of these complexes lead to the identification of hydrophobic patches, hydrogen-bonds, and salt bridges as three essential forces mediating the interactions between this channel and the toxins, in which four Kv1.2-specific interacting amino acids (D353, Q358, V381, and T383) are identified for the first time. This discovery might help design highly selective Kv1.2-channel inhibitors by altering amino acids of these toxins binding to the four channel residues. Finally, our results provide new evidence in favor of an induced fit model between scorpion toxins and K+ channel interactions.
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Affiliation(s)
- Shouli Yuan
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Bin Gao
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Shunyi Zhu
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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8
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Wu W, Li Z, Ma Y. Adaptive evolution of insect selective excitatory β-type sodium channel neurotoxins from scorpion venom. Peptides 2017; 92:31-37. [PMID: 28363794 DOI: 10.1016/j.peptides.2017.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Abstract
Insect selective excitatory β-type sodium channel neurotoxins from scorpion venom (β-NaScTxs) are composed of about 70-76 amino acid residues and share a common scaffold stabilized by four unique disulfide bonds. The phylogenetic analysis of these toxins was hindered by limited sequence data. In our recent study, two new insect selective excitatory β-NaScTxs, LmIT and ImIT, were isolated from Lychas mucronatus and Isometrus maculatus, respectively. With the sequences previously reported, we examined the adaptive molecular evolution of insect selective excitatory β-NaScTxs by estimating the nonsynonymous-to-synonymous rate ratio (ω=dN/dS). The results revealed 12 positively selected sites in the genes of insect selective excitatory β-NaScTxs. Moreover, these positively selected sites match well with the sites important for interacting with sodium channels, as demonstrated in previous mutagenesis study. These results reveal that adaptive evolution after gene duplication is one of the most important genetic mechanisms of scorpion neurotoxin diversification.
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Affiliation(s)
- Wenlan Wu
- Medical School, Henan University of Science and Technology, Luoyang, Henan Province, PR China.
| | - Zhongjie Li
- Medical School, Henan University of Science and Technology, Luoyang, Henan Province, PR China
| | - Yibao Ma
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.
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9
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Kuyucak S, Kayser V. Biobetters From an Integrated Computational/Experimental Approach. Comput Struct Biotechnol J 2017; 15:138-145. [PMID: 28179976 PMCID: PMC5279740 DOI: 10.1016/j.csbj.2017.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 02/04/2023] Open
Abstract
Biobetters are new drugs designed from existing peptide or protein-based therapeutics by improving their properties such as affinity and selectivity for the target epitope, and stability against degradation. Computational methods can play a key role in such design problems—by predicting the changes that are most likely to succeed, they can drastically reduce the number of experiments to be performed. Here we discuss the computational and experimental methods commonly used in drug design problems, focusing on the inverse relationship between the two, namely, the more accurate the computational predictions means the less experimental effort is needed for testing. Examples discussed include efforts to design selective analogs from toxin peptides targeting ion channels for treatment of autoimmune diseases and monoclonal antibodies which are the fastest growing class of therapeutic agents particularly for cancers and autoimmune diseases.
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Affiliation(s)
- Serdar Kuyucak
- School of Physics, University of Sydney, NSW 2006, Australia
- Corresponding author.
| | - Veysel Kayser
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
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10
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Hamzeh-Mivehroud M, Sokouti B, Dastmalchi S. Molecular Docking at a Glance. Oncology 2017. [DOI: 10.4018/978-1-5225-0549-5.ch030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The current chapter introduces different aspects of molecular docking technique in order to give an overview to the readers about the topics which will be dealt with throughout this volume. Like many other fields of science, molecular docking studies has experienced a lagging period of slow and steady increase in terms of acquiring attention of scientific community as well as its frequency of application, followed by a pronounced era of exponential expansion in theory, methodology, areas of application and performance due to developments in related technologies such as computational resources and theoretical as well as experimental biophysical methods. In the following sections the evolution of molecular docking will be reviewed and its different components including methods, search algorithms, scoring functions, validation of the methods, and area of applications plus few case studies will be touched briefly.
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Affiliation(s)
| | | | - Siavoush Dastmalchi
- Biotechnology Research Center, Tabriz University of Medical Sciences, Iran & School of Pharmacy, Tabriz University of Medical Sciences, Iran
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11
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Ye F, Hu Y, Yu W, Xie Z, Hu J, Cao Z, Li W, Wu Y. The Scorpion Toxin Analogue BmKTX-D33H as a Potential Kv1.3 Channel-Selective Immunomodulator for Autoimmune Diseases. Toxins (Basel) 2016; 8:115. [PMID: 27104568 PMCID: PMC4848641 DOI: 10.3390/toxins8040115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 01/23/2023] Open
Abstract
The Kv1.3 channel-acting scorpion toxins usually adopt the conserved anti-parallel β-sheet domain as the binding interface, but it remains challenging to discover some highly selective Kv1.3 channel-acting toxins. In this work, we investigated the pharmacological profile of the Kv1.3 channel-acting BmKTX-D33H, a structural analogue of the BmKTX scorpion toxin. Interestingly, BmKTX-D33H, with its conserved anti-parallel β-sheet domain as a Kv1.3 channel-interacting interface, exhibited more than 1000-fold selectivity towards the Kv1.3 channel as compared to other K+ channels (including Kv1.1, Kv1.2, Kv1.7, Kv11.1, KCa2.2, KCa2.3, and KCa3.1). As expected, BmKTX-D33H was found to inhibit the cytokine production and proliferation of both Jurkat cells and human T cells in vitro. It also significantly improved the delayed-type hypersensitivity (DTH) responses, an autoreactive T cell-mediated inflammation in rats. Amino acid sequence alignment and structural analysis strongly suggest that the “evolutionary” Gly11 residue of BmKTX-D33H interacts with the turret domain of Kv1 channels; it appears to be a pivotal amino acid residue with regard to the selectivity of BmKTX-D33H towards the Kv1.3 channel (in comparison with the highly homologous scorpion toxins). Together, our data indicate that BmKTX-D33H is a Kv1.3 channel–specific blocker. Finally, the remarkable selectivity of BmKTX-D33H highlights the great potential of evolutionary-guided peptide drug design in future studies.
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Affiliation(s)
- Fang Ye
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Youtian Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Weiwei Yu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zili Xie
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Jun Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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12
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Meng L, Xie Z, Zhang Q, Li Y, Yang F, Chen Z, Li W, Cao Z, Wu Y. Scorpion Potassium Channel-blocking Defensin Highlights a Functional Link with Neurotoxin. J Biol Chem 2016; 291:7097-106. [PMID: 26817841 DOI: 10.1074/jbc.m115.680611] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 01/01/2023] Open
Abstract
The structural similarity between defensins and scorpion neurotoxins suggests that they might have evolved from a common ancestor. However, there is no direct experimental evidence demonstrating a functional link between scorpion neurotoxins and defensins. The scorpion defensin BmKDfsin4 from Mesobuthus martensiiKarsch contains 37 amino acid residues and a conserved cystine-stabilized α/β structural fold. The recombinant BmKDfsin4, a classical defensin, has been found to have inhibitory activity against Gram-positive bacteria such as Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteusas well as methicillin-resistant Staphylococcus aureus Interestingly, electrophysiological experiments showed that BmKDfsin4,like scorpion potassium channel neurotoxins, could effectively inhibit Kv1.1, Kv1.2, and Kv1.3 channel currents, and its IC50value for the Kv1.3 channel was 510.2 nm Similar to the structure-function relationships of classical scorpion potassium channel-blocking toxins, basic residues (Lys-13 and Arg-19) of BmKDfsin4 play critical roles in peptide-Kv1.3 channel interactions. Furthermore, mutagenesis and electrophysiological experiments demonstrated that the channel extracellular pore region is the binding site of BmKDfsin4, indicating that BmKDfsin4 adopts the same mechanism for blocking potassium channel currents as classical scorpion toxins. Taken together, our work identifies scorpion BmKDfsin4 as the first invertebrate defensin to block potassium channels. These findings not only demonstrate that defensins from invertebrate animals are a novel type of potassium channel blockers but also provide evidence of a functional link between defensins and neurotoxins.
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Affiliation(s)
- Lanxia Meng
- From the State Key Laboratory of Virology, College of Life Sciences and
| | - Zili Xie
- From the State Key Laboratory of Virology, College of Life Sciences and
| | - Qian Zhang
- From the State Key Laboratory of Virology, College of Life Sciences and
| | - Yang Li
- From the State Key Laboratory of Virology, College of Life Sciences and
| | - Fan Yang
- From the State Key Laboratory of Virology, College of Life Sciences and
| | - Zongyun Chen
- From the State Key Laboratory of Virology, College of Life Sciences and
| | - Wenxin Li
- From the State Key Laboratory of Virology, College of Life Sciences and Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Zhijian Cao
- From the State Key Laboratory of Virology, College of Life Sciences and Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Yingliang Wu
- From the State Key Laboratory of Virology, College of Life Sciences and Center for BioDrug Research, Wuhan University, Wuhan 430072, China
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13
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Computational Studies of Venom Peptides Targeting Potassium Channels. Toxins (Basel) 2015; 7:5194-211. [PMID: 26633507 PMCID: PMC4690127 DOI: 10.3390/toxins7124877] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 11/13/2015] [Accepted: 11/20/2015] [Indexed: 01/18/2023] Open
Abstract
Small peptides isolated from the venom of animals are potential scaffolds for ion channel drug discovery. This review article mainly focuses on the computational studies that have advanced our understanding of how various toxins interfere with the function of K+ channels. We introduce the computational tools available for the study of toxin-channel interactions. We then discuss how these computational tools have been fruitfully applied to elucidate the mechanisms of action of a wide range of venom peptides from scorpions, spiders, and sea anemone.
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14
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Chen Z, Hu Y, Wang B, Cao Z, Li W, Wu Y. A single conserved basic residue in the potassium channel filter region controls KCNQ1 insensitivity toward scorpion toxins. Biochem Biophys Rep 2015; 3:62-67. [PMID: 29124168 PMCID: PMC5668678 DOI: 10.1016/j.bbrep.2015.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 07/05/2015] [Accepted: 07/07/2015] [Indexed: 02/06/2023] Open
Abstract
Although many studies concerning the sensitivity mechanism of scorpion toxin-potassium channel interactions have been reported, few have explored the biochemical insensitivity mechanisms of potassium channel receptors toward natural scorpion toxin peptides, such as the KCNQ1 channel. Here, by sequence alignment analyses of the human KCNQ1 channel and scorpion potassium channel MmKv2, which is completely insensitive to scorpion toxins, we proposed that the insensitivity mechanism of KCNQ1 toward natural scorpion toxins might involve two functional regions, the turret and filter regions. Based on this observation, a series of KCNQ1 mutants were constructed to study molecular mechanisms of the KCNQ1 channel insensitivity toward natural scorpion toxins. Electrophysiological studies of chimera channels showed that the channel filter region controls KCNQ1 insensitivity toward the classical scorpion toxin ChTX. Interestingly, further residue mutant experiments showed that a single basic residue in the filter region determined the insensitivity of KCNQ1 channels toward scorpion toxins. Our present work showed that amino acid residue diversification at common sites controls the sensitivity and insensitivity of potassium channels toward scorpion toxins. The unique insensitivity mechanism of KCNQ1 toward natural scorpion toxins will accelerate the rational design of potent peptide inhibitors toward this channel. Insensitivity mechanism of KCNQ1 towards scorpion toxins was still unclear. A single basic residue in the KCNQ1 filter region controls its insensitivity. Amino acid residue diversification controls KCNQ1 sensitivity and insensitivity. Our work will accelerate rational design of KCNQ1 peptide inhibitors.
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Affiliation(s)
- Zongyun Chen
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Hubei University of Medicine, Hubei, China.,State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, China
| | - Youtian Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, China
| | - Bin Wang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, China
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, China
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15
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Computational approaches for designing potent and selective analogs of peptide toxins as novel therapeutics. Future Med Chem 2015; 6:1645-58. [PMID: 25406005 DOI: 10.4155/fmc.14.98] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Peptide toxins provide valuable therapeutic leads for many diseases. As they bind to their targets with high affinity, potency is usually ensured. However, toxins also bind to off-target receptors, causing potential side effects. Thus, a major challenge in generating drugs from peptide toxins is ensuring their specificity for their intended targets. Computational methods can play an important role in solving such design problems through construction of accurate models of receptor-toxin complexes and calculation of binding free energies. Here we review the computational methods used for this purpose and their application to toxins targeting ion channels. We describe ShK and HsTX1 toxins, high-affinity blockers of the voltage-gated potassium channel Kv1.3, which could be developed as therapeutic agents for autoimmune diseases.
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16
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Chen R, Chung SH. Binding modes of two scorpion toxins to the voltage-gated potassium channel kv1.3 revealed from molecular dynamics. Toxins (Basel) 2014; 6:2149-61. [PMID: 25054783 PMCID: PMC4113748 DOI: 10.3390/toxins6072149] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/08/2014] [Accepted: 07/10/2014] [Indexed: 12/13/2022] Open
Abstract
Molecular dynamics (MD) simulations are used to examine the binding modes of two scorpion toxins, margatoxin (MgTx) and hongotoxin (HgTx), to the voltage gated K+ channel, Kv1.3. Using steered MD simulations, we insert either Lys28 or Lys35 of the toxins into the selectivity filter of the channel. The MgTx-Kv1.3 complex is stable when the side chain of Lys35 from the toxin occludes the channel filter, suggesting that Lys35 is the pore-blocking residue for Kv1.3. In this complex, Lys28 of the toxin forms one additional salt bridge with Asp449 just outside the filter of the channel. On the other hand, HgTx forms a stable complex with Kv1.3 when the side chain of Lys28 but not Lys35 protrudes into the filter of the channel. A survey of all the possible favorable binding modes of HgTx-Kv1.3 is carried out by rotating the toxin at 3° intervals around the channel axis while the position of HgTx-Lys28 relative to the filter is maintained. We identify two possible favorable binding modes: HgTx-Arg24 can interact with either Asp433 or Glu420 on the vestibular wall of the channel. The dissociation constants calculated from the two binding modes of HgTx-Kv1.3 differ by approximately 20 fold, suggesting that the two modes are of similar energetics.
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Affiliation(s)
- Rong Chen
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
| | - Shin-Ho Chung
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
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17
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Hu YT, Hu J, Li T, Wei JJ, Feng J, Du YM, Cao ZJ, Li WX, Wu YL. Open conformation of hERG channel turrets revealed by a specific scorpion toxin BmKKx2. Cell Biosci 2014; 4:18. [PMID: 24725272 PMCID: PMC4108063 DOI: 10.1186/2045-3701-4-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 02/11/2014] [Indexed: 11/23/2022] Open
Abstract
Background The human ether-a-go-go-related gene potassium channel (hERG) has an unusual long turret, whose role in recognizing scorpion toxins remains controversial. Here, BmKKx2, the first specific blocker of hERG channel derived from scorpion Mesobuthus martensii, was identified and the turret role of hERG channel was re-investigated using BmKKx2 as a molecular probe. Results BmKKx2 was found to block hERG channel with an IC50 of 6.7 ± 1.7 nM and share similar functional surface with the known hERG channel inhibitor BeKm-1. The alanine-scanning mutagenesis data indicate that different residue substitutions on hERG channel by alanine decreased the affinities of toxin BmKKx2 by about 10-fold compared with that of wild-type hERG channel, which reveals that channel turrets play a secondary role in toxin binding. Different from channel turret, the pore region of hERG channel was found to exert the conserved and essential function for toxin binding because the mutant hERG-S631A channel remarkably decreased toxin BmKKx2 affinity by about 104-fold. Conclusions Our results not only revealed that channel turrets of hERG channel formed an open conformation in scorpion toxin binding, but also enriched the diversity of structure-function relationships among the different potassium channel turrets.
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Affiliation(s)
- You-Tian Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jun Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Tian Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jing-Jing Wei
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jing Feng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yi-Mei Du
- Research Center of Ion Channelopathy, Institute of Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zhi-Jian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Wen-Xin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ying-Liang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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18
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Luna-Ramírez K, Bartok A, Restano-Cassulini R, Quintero-Hernández V, Coronas FIV, Christensen J, Wright CE, Panyi G, Possani LD. Structure, Molecular Modeling, and Function of the Novel Potassium Channel Blocker Urotoxin Isolated from the Venom of the Australian Scorpion Urodacus yaschenkoi. Mol Pharmacol 2014; 86:28-41. [DOI: 10.1124/mol.113.090183] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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19
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Unusual binding mode of scorpion toxin BmKTX onto potassium channels relies on its distribution of acidic residues. Biochem Biophys Res Commun 2014; 447:70-6. [DOI: 10.1016/j.bbrc.2014.03.101] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 03/20/2014] [Indexed: 01/12/2023]
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20
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Cao Z, Di Z, Wu Y, Li W. Overview of scorpion species from China and their toxins. Toxins (Basel) 2014; 6:796-815. [PMID: 24577583 PMCID: PMC3968362 DOI: 10.3390/toxins6030796] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/16/2014] [Accepted: 01/18/2014] [Indexed: 12/29/2022] Open
Abstract
Scorpions are one of the most ancient groups of terrestrial animals. They have maintained a steady morphology over more than 400 million years of evolution. Their venom arsenals for capturing prey and defending against predators may play a critical role in their ancient and conservative appearance. In the current review, we present the scorpion fauna of China: 53 species covering five families and 12 genera. We also systematically list toxins or genes from Chinese scorpion species, involving eight species covering four families. Furthermore, we review the diverse functions of typical toxins from Chinese scorpion species, involving Na+ channel modulators, K+ channel blockers, antimicrobial peptides and protease inhibitors. Using scorpion species and their toxins from China as an example, we build the bridge between scorpion species and their toxins, which helps us to understand the molecular and functional diversity of scorpion venom arsenal, the dynamic and functional evolution of scorpion toxins, and the potential relationships of scorpion species and their toxins.
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Affiliation(s)
- Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zhiyong Di
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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21
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Kv1.3 potassium channel-blocking toxin Ctri9577, novel gating modifier of Kv4.3 potassium channel from the scorpion toxin family. Biochem Biophys Res Commun 2014; 444:406-10. [DOI: 10.1016/j.bbrc.2014.01.094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 01/19/2014] [Indexed: 01/11/2023]
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22
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Rashid MH, Kuyucak S. Free Energy Simulations of Binding of HsTx1 Toxin to Kv1 Potassium Channels: the Basis of Kv1.3/Kv1.1 Selectivity. J Phys Chem B 2014; 118:707-16. [DOI: 10.1021/jp410950h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- M. Harunur Rashid
- School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Serdar Kuyucak
- School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
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23
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Ma J, Hu Y, Guo M, Huang Z, Li W, Wu Y. hERG potassium channel blockage by scorpion toxin BmKKx2 enhances erythroid differentiation of human leukemia cells K562. PLoS One 2013; 8:e84903. [PMID: 24386436 PMCID: PMC3873423 DOI: 10.1371/journal.pone.0084903] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/28/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The hERG potassium channel can modulate the proliferation of the chronic myelogenous leukemic K562 cells, and its role in the erythroid differentiation of K562 cells still remains unclear. PRINCIPAL FINDINGS The hERG potassium channel blockage by a new 36-residue scorpion toxin BmKKx2, a potent hERG channel blocker with IC50 of 6.7 ± 1.7 nM, enhanced the erythroid differentiation of K562 cells. The mean values of GPA (CD235a) fluorescence intensity in the group of K562 cells pretreated by the toxin for 24 h and followed by cytosine arabinoside (Ara-C) treatment for 72 h were about 2-fold stronger than those of K562 cells induced by Ara-C alone. Such unique role of hERG potassium channel was also supported by the evidence that the effect of the toxin BmKKx2 on cell differentiation was nullified in hERG-deficient cell lines. During the K562 cell differentiation, BmKKx2 could also suppress the expression of hERG channels at both mRNA and protein levels. Besides the function of differentiation enhancement, BmKKx2 was also found to promote the differentiation-dependent apoptosis during the differentiation process of K562 cells. In addition, the blockage of hERG potassium channel by toxin BmKKx2 was able to decrease the intracellular Ca(2+) concentration during the K562 cell differentiation, providing an insight into the mechanism of hERG potassium channel regulating this cellular process. CONCLUSIONS/SIGNIFICANCE Our results revealed scorpion toxin BmKKx2 could enhance the erythroid differentiation of leukemic K562 cells via inhibiting hERG potassium channel currents. These findings would not only accelerate the functional research of hERG channel in different leukemic cells, but also present the prospects of natural scorpion toxins as anti-leukemic drugs.
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Affiliation(s)
- Jian Ma
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Youtian Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Mingxiong Guo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zan Huang
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail: (WL); (YW)
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail: (WL); (YW)
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24
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Hu J, Qiu S, Yang F, Cao Z, Li W, Wu Y. Unique mechanism of the interaction between honey bee toxin TPNQ and rKir1.1 potassium channel explored by computational simulations: insights into the relative insensitivity of channel towards animal toxins. PLoS One 2013; 8:e67213. [PMID: 23874410 PMCID: PMC3707903 DOI: 10.1371/journal.pone.0067213] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 05/15/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The 21-residue compact tertiapin-Q (TPNQ) toxin, a derivative of honey bee toxin tertiapin (TPN), is a potent blocker of inward-rectifier K(+) channel subtype, rat Kir1.1 (rKir1.1) channel, and their interaction mechanism remains unclear. PRINCIPAL FINDINGS Based on the flexible feature of potassium channel turrets, a good starting rKir1.1 channel structure was modeled for the accessibility of rKir1.1 channel turrets to TPNQ toxin. In combination with experimental alanine scanning mutagenesis data, computational approaches were further used to obtain a reasonable TPNQ toxin-rKir1.1 channel complex structure, which was completely different from the known binding modes between animal toxins and potassium channels. TPNQ toxin mainly adopted its helical domain as the channel-interacting surface together with His12 as the pore-blocking residue. The important Gln13 residue mainly contacted channel residues near the selectivity filter, and Lys20 residue was surrounded by a polar "groove" formed by Arg118, Thr119, Glu123, and Asn124 in the channel turret. On the other hand, four turrets of rKir1.1 channel gathered to form a narrow pore entryway for TPNQ toxin recognition. The Phe146 and Phe148 residues in the channel pore region formed strong hydrophobic protrusions, and produced dominant nonpolar interactions with toxin residues. These specific structure features of rKir1.1 channel vestibule well matched the binding of potent TPNQ toxin, and likely restricted the binding of the classical animal toxins. CONCLUSIONS/SIGNIFICANCE The TPNQ toxin-rKir1.1 channel complex structure not only revealed their unique interaction mechanism, but also would highlight the diverse animal toxin-potassium channel interactions, and elucidate the relative insensitivity of rKir1.1 channel towards animal toxins.
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Affiliation(s)
- Jun Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, PR China
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25
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Gordon D, Chen R, Chung SH. Computational methods of studying the binding of toxins from venomous animals to biological ion channels: theory and applications. Physiol Rev 2013; 93:767-802. [PMID: 23589832 PMCID: PMC3768100 DOI: 10.1152/physrev.00035.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The discovery of new drugs that selectively block or modulate ion channels has great potential to provide new treatments for a host of conditions. One promising avenue revolves around modifying or mimicking certain naturally occurring ion channel modulator toxins. This strategy appears to offer the prospect of designing drugs that are both potent and specific. The use of computational modeling is crucial to this endeavor, as it has the potential to provide lower cost alternatives for exploring the effects of new compounds on ion channels. In addition, computational modeling can provide structural information and theoretical understanding that is not easily derivable from experimental results. In this review, we look at the theory and computational methods that are applicable to the study of ion channel modulators. The first section provides an introduction to various theoretical concepts, including force-fields and the statistical mechanics of binding. We then look at various computational techniques available to the researcher, including molecular dynamics, brownian dynamics, and molecular docking systems. The latter section of the review explores applications of these techniques, concentrating on pore blocker and gating modifier toxins of potassium and sodium channels. After first discussing the structural features of these channels, and their modes of block, we provide an in-depth review of past computational work that has been carried out. Finally, we discuss prospects for future developments in the field.
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Affiliation(s)
- Dan Gordon
- Research School of Biology, The Australian National University, Acton, ACT 0200, Australia.
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26
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Computational studies of marine toxins targeting ion channels. Mar Drugs 2013; 11:848-69. [PMID: 23528952 PMCID: PMC3705375 DOI: 10.3390/md11030848] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 01/30/2013] [Accepted: 02/07/2013] [Indexed: 12/18/2022] Open
Abstract
Toxins from marine animals offer novel drug leads for treatment of diseases involving ion channels. Computational methods could be very helpful in this endeavour in several ways, e.g., (i) constructing accurate models of the channel-toxin complexes using docking and molecular dynamics (MD) simulations; (ii) determining the binding free energies of toxins from umbrella sampling MD simulations; (iii) predicting the effect of mutations from free energy MD simulations. Using these methods, one can design new analogs of toxins with improved affinity and selectivity properties. Here we present a review of the computational methods and discuss their applications to marine toxins targeting potassium and sodium channels. Detailed examples from the potassium channel toxins—ShK from sea anemone and κ-conotoxin PVIIA—are provided to demonstrate capabilities of the computational methods to give accurate descriptions of the channel-toxin complexes and the energetics of their binding. An example is also given from sodium channel toxins (µ-conotoxin GIIIA) to illustrate the differences between the toxin binding modes in potassium and sodium channels.
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27
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Mahdavi S, Kuyucak S. Why the Drosophila Shaker K+ channel is not a good model for ligand binding to voltage-gated Kv1 channels. Biochemistry 2013; 52:1631-40. [PMID: 23398369 DOI: 10.1021/bi301257p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The Drosophila Shaker K(+) channel is the first cloned voltage-gated potassium channel and has, therefore, played an important role in structural and functional studies of those channels. While such a role is well justified for ion permeation, it is not clear whether this also extends to ligand binding. Despite the high degree of homology among Shaker and Kv1 channels, κ-conotoxin PVIIA (κ-PVIIA) binds to Shaker with high affinity but not to Kv1 channels. Here we address this issue by studying binding of κ-PVIIA to Shaker and Kv1 channels using molecular dynamics (MD) simulations. The structures of the channel-toxin complexes are constructed via docking and refinement with MD. The binding mode of each complex is characterized and compared to available mutagenesis data to validate the complex models. The potential of mean force for dissociation of the Shaker-κ-PVIIA complex is calculated from umbrella sampling MD simulations, and the corresponding binding free energy is determined, which provides further validation of the complex structure. Comparison of the Shaker and Kv1 complex models shows that a few mutations in the turret and extended regions are sufficient to abolish the observed sensitivity of Shaker to κ-PVIIA. This study demonstrates that Shaker is not always a good model for Kv1 channels for ligand binding. It also provides insights into the binding of the toxin to potassium channels that will be useful for improving affinity and selectivity properties of Kv1 channels.
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Affiliation(s)
- Somayeh Mahdavi
- School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
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28
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Chen R, Chung SH. Structural basis of the selective block of Kv1.2 by maurotoxin from computer simulations. PLoS One 2012; 7:e47253. [PMID: 23071772 PMCID: PMC3468451 DOI: 10.1371/journal.pone.0047253] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 09/12/2012] [Indexed: 12/22/2022] Open
Abstract
The 34-residue polypeptide maurotoxin (MTx) isolated from scorpion venoms selectively inhibits the current of the voltage-gated potassium channel Kv1.2 by occluding the ion conduction pathway. Here using molecular dynamics simulation as a docking method, the binding modes of MTx to three closely related channels (Kv1.1, Kv1.2 and Kv1.3) are examined. We show that MTx forms more favorable electrostatic interactions with the outer vestibule of Kv1.2 compared to Kv1.1 and Kv1.3, consistent with the selectivity of MTx for Kv1.2 over Kv1.1 and Kv1.3 observed experimentally. One salt bridge in the bound complex of MTx-Kv1.2 forms and breaks in a simulation period of 20ns, suggesting the dynamic nature of toxin-channel interactions. The toxin selectivity likely arises from the differences in the shape of the channel outer vestibule, giving rise to distinct orientations of MTx on block. Potential of mean force calculations show that MTx blocks Kv1.1, Kv1.2 and Kv1.3 with an IC50 value of 6 µM, 0.6nM and 18 µM, respectively.
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Affiliation(s)
- Rong Chen
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (RC); (S-HC)
| | - Shin-Ho Chung
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (RC); (S-HC)
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29
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Yan JJ, Zhang YB, Ding Y. Binding mechanism between Hsp90 and Sgt1 explored by homology modeling and molecular dynamics simulations in rice. J Mol Model 2012; 18:4665-73. [PMID: 22653607 DOI: 10.1007/s00894-012-1464-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 05/11/2012] [Indexed: 01/03/2023]
Abstract
The Hsp90 (for heat shock protein90) and the Sgt1 (for suppressor of the G2 allele of skp1) are widely distributed in animals, yeast, and plants. The former functions as molecular chaperon activating a series of client proteins, the latter functions as an adaptor protein participating in multiple biological processes such as immunity response through interactions with different protein complexes. In the present study, we have constructed a homology model of Hsp90-Sgt1 complex in rice based on a recently resolved structure from barley and Arabidopsis to explore its binding mechanisms and to understand the detailed interaction profile. A total of 20 ns explicit solvent molecular dynamics simulations combined with MM-GBSA computations and virtual alanine scanning were performed for the modeled complex. In the final structure, three strong salt bridges were found between OsHsp90 and OsSgt1, D217(OsHsp90)-K186(OsSgt1), D218(OsHsp90)-K237(OsSgt1) and K161(OsHsp90)-E239(OsSgt1). Besides, residue Y173 of OsSgt1 played a vital role in the interactions with OsHsp90, the detailed interactions were discussed. These results would help us understand the critical features determining the Hsp90-Sgt1 binding process.
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Affiliation(s)
- Jun-jie Yan
- State Key Laboratory of Hybrid Rice, Department of Genetics, College of Life Sciences, Wuhan University, Wuhan 430072, People's Republic of China
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30
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Chen PC, Kuyucak S. Accurate determination of the binding free energy for KcsA-charybdotoxin complex from the potential of mean force calculations with restraints. Biophys J 2011; 100:2466-74. [PMID: 21575581 DOI: 10.1016/j.bpj.2011.03.052] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 03/20/2011] [Accepted: 03/28/2011] [Indexed: 11/19/2022] Open
Abstract
Free energy calculations for protein-ligand dissociation have been tested and validated for small ligands (50 atoms or less), but there has been a paucity of studies for larger, peptide-size ligands due to computational limitations. Previously we have studied the energetics of dissociation in a potassium channel-charybdotoxin complex by using umbrella sampling molecular-dynamics simulations, and established the need for carefully chosen coordinates and restraints to maintain the physiological ligand conformation. Here we address the ligand integrity problem further by constructing additional potential of mean forces for dissociation of charybdotoxin using restraints. We show that the large discrepancies in binding free energy arising from simulation artifacts can be avoided by using appropriate restraints on the ligand, which enables determination of the binding free energy within the chemical accuracy. We make several suggestions for optimal choices of harmonic potential parameters and restraints to be used in binding studies of large ligands.
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Affiliation(s)
- Po-Chia Chen
- School of Physics, University of Sydney, Sydney, New South Wales, Australia
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Pan D, Yan Q, Chen Y, McDonald JM, Song Y. Trifluoperazine regulation of calmodulin binding to Fas: a computational study. Proteins 2011; 79:2543-56. [PMID: 21656570 PMCID: PMC3132223 DOI: 10.1002/prot.23081] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 04/26/2011] [Accepted: 05/04/2011] [Indexed: 12/13/2022]
Abstract
Death-inducing signaling complex (DISC) formation is a critical step in Fas-mediated signaling for apoptosis. Previous experiments have demonstrated that the calmodulin (CaM) antagonist, trifluoperazine (TFP) regulates CaM-Fas binding and affects Fas-mediated DISC formation. In this study, we investigated the anti-cooperative characteristics of TFP binding to CaM and the effect of TFP on the CaM-Fas interaction from both structural and thermodynamic perspectives using combined molecular dynamics simulations and binding free energy analyses. We studied the interactions of different numbers of TFP molecules with CaM and explored the effects of the resulting conformational changes in CaM on CaM-Fas binding. Results from these analyses showed that the number of TFP molecules bound to CaM directly influenced α-helix formation and hydrogen bond occupancy within the α-helices of CaM, contributing to the conformational and motion changes in CaM. These changes affected CaM binding to Fas, resulting in secondary structural changes in Fas and conformational and motion changes of Fas in CaM-Fas complexes, potentially perturbing the recruitment of Fas-associated death domain for DISC formation. The computational results from this study reveal the structural and molecular mechanisms that underlie the role of the CaM antagonist, TFP, in regulation of CaM-Fas binding and Fas-mediated DISC formation in a concentration-dependent manner.
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Affiliation(s)
- Di Pan
- Department of Biomedical Engineering, The University of Alabama at Birmingham, AL 35294
| | - Qi Yan
- Department of Biomedical Engineering, The University of Alabama at Birmingham, AL 35294
| | - Yabing Chen
- Department of Pathology, The University of Alabama at Birmingham, AL 35294
- VA Medical Center Birmingham, AL 35294
| | - Jay M McDonald
- Department of Pathology, The University of Alabama at Birmingham, AL 35294
- VA Medical Center Birmingham, AL 35294
| | - Yuhua Song
- Department of Biomedical Engineering, The University of Alabama at Birmingham, AL 35294
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Jin L, Wu Y. Molecular mechanism of δ-dendrotoxin-potassium channel recognition explored by docking and molecular dynamic simulations. J Mol Recognit 2011; 24:101-7. [PMID: 21194120 DOI: 10.1002/jmr.1031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
δ-Dendrotoxin, isolated from mamba snake venom, has 57 residues cross-linked by three disulfide bridges. The protein shares a pharmacological activity with other animal toxins, the potent blockade of potassium channels, but is structurally unrelated to toxins of different species. We employed alanine-scanning mutagenesis to explore the molecular mechanism of δ-dendrotoxin binding to potassium channels, using protein-protein docking and molecular dynamic simulations. In our reasonable model of the δ-dendrotoxin-ShaKv1.1 complex, δ-dendrotoxin interacted mainly with the N-terminal region and the turn of two antiparallel β-sheets of the channel. This binding mode could well explain the functional roles of critical residues in δ-dendrotoxin and the ShaKv1.1 channel. Structural analysis indicated that the critical Lys6 residue of δ-dendrotoxin plugged its side chain into a channel selectivity filter. Another two critical δ-dendrotoxin residues, Lys3 and Arg10, were found to contact channel residues through strong polar and nonpolar interactions, especially salt-bridge interactions. As for the ShaKv1.1 channel, the channel turrets were found in the "half-open state," and two of four Glu423 in the turrets of the channel B and D chains could interact, respectively, with Lys3 and Lys26 of δ-dendrotoxin through electrostatic interactions. The essential Asp431 channel residue was found to associate electrostatically with Arg10 of δ-dendrotoxin, and a critical Tyr449 channel residue was just under the channel-interacting surface of δ-dendrotoxin. Together, these novel data may accelerate the structure-function research of toxins in the dendrotoxin family and be of significant value in revealing the diverse interactions between animal toxins and potassium channels.
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Affiliation(s)
- Ling Jin
- Department of Chemistry, School of Natural Science, Wuhan University of Technology, Wuhan, Hubei 430070, P.R. China.
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33
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Ponomarev SY, Audie J. Computational prediction and analysis of the DR6-NAPP interaction. Proteins 2011; 79:1376-95. [DOI: 10.1002/prot.22962] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 11/02/2010] [Accepted: 11/24/2010] [Indexed: 01/14/2023]
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Yi H, Qiu S, Wu Y, Li W, Wang B. Differential molecular information of maurotoxin peptide recognizing IK(Ca) and Kv1.2 channels explored by computational simulation. BMC STRUCTURAL BIOLOGY 2011; 11:3. [PMID: 21262000 PMCID: PMC3041654 DOI: 10.1186/1472-6807-11-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 01/25/2011] [Indexed: 12/19/2022]
Abstract
BACKGROUND Scorpion toxins are invaluable tools for ion channel research and are potential drugs for human channelopathies. However, it is still an open task to determine the molecular basis underlying the diverse interactions between toxin peptides and ion channels. The inhibitory peptide Maurotoxin (MTX) recognized the distantly related IK(Ca) and Kv1.2 channel with approximately the same potency and using the same functional residues, their differential binding mechanism remain elusive. In this study, we applied computational methods to explore the differential binding modes of MTX to Kv1.2 and IK(Ca) channels, which would help to understand the diversity of channel-toxin interactions and accelerate the toxin-based drug design. RESULTS A reasonably stable MTX-IK(Ca) complex was obtained by combining various computational methods and by in-depth comparison with the previous model of the MTX-Kv1.2 complex. Similarly, MTX adopted the β-sheet structure as the interacting surface for binding both channels, with Lys23 occluding the pore. In contrast, the other critical residues Lys27, Lys30, and Tyr32 of MTX adopted distinct interactions when associating with the IK(Ca) channel. In addition, the residues Gln229, Ala230, Ala233, and Thr234 on the IK(Ca) channel turret formed polar and non-polar interactions with MTX, whereas the turret of Kv1.2 was almost not involved in recognizing MTX. In all, the pairs of interacting residues on MTX and the IK(Ca) channel of the bound complex indicated that electrostatic and Van der Waal interactions contributed equally to the formation of a stable MTX-IK(Ca) complex, in contrast to the MTX-Kv1.2 binding that is dominantly mediated by electrostatic forces. CONCLUSIONS Despite sharing similar pharmacological profiles toward both IK(Ca) and Kv1.2 channels, MTX adopted totally diverging modes in the two association processes. All the molecular information unveiled here could not only offer a better understanding about the structural differences between the IK(Ca) and Kv1.2 channels, but also provide novel structural clues that will help in the designing of more selective molecular probes to discriminate between these two channels.
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Affiliation(s)
- Hong Yi
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
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Han S, Hu Y, Zhang R, Yi H, Wei J, Wu Y, Cao Z, Li W, He X. ImKTx88, a novel selective Kv1.3 channel blocker derived from the scorpion Isometrus maculates. Toxicon 2010; 57:348-55. [PMID: 21194541 DOI: 10.1016/j.toxicon.2010.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/20/2010] [Accepted: 12/20/2010] [Indexed: 01/15/2023]
Abstract
Scorpion toxins are useful in the structure-function research of ion channels and valuable resources for drug design. The Kv1.3 channel is an important pharmacological target for the therapy of T cell-mediated autoimmune diseases, and many toxin peptides targeting Kv1.3 have been identified as good drug candidates in recent years. In this study, a novel toxin gene ImKTx88 was isolated from the venom of the scorpion Isometrus maculates through the construction of the cDNA library method, and the recombinant toxin peptide was purified and characterized physiologically. The mature peptide of ImKTx88 contained 39 amino acid residues including six cysteines and was predicted to be a new member of α-KTx scorpion family by sequence analysis. The electrophysiological experiments further indicated that the rImKTx88 peptide had a novel pharmacological profile: it inhibited Kv1.3 channel current with an IC₅₀ of 91 ± 42 pM, and exhibited very good selectivity for Kv1.3 over Kv1.1 (4200-fold) and Kv1.2 (93000-fold) channels, respectively. All these results suggested that, as a new selective Kv1.3 channel blocker, the ImKTx88 peptide may serve as a potential drug candidate in the therapy of autoimmune diseases.
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Affiliation(s)
- Song Han
- School of Medicine, Wuhan University, Wuhan 430071, People's Republic of China
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Zhang Y, Baaden M, Yan J, Shao J, Qiu S, Wu Y, Ding Y. The Molecular Recognition Mechanism for Superoxide Dismutase Presequence Binding to the Mitochondrial Protein Import Receptor Tom20 from Oryza sativa Involves an LRTLA Motif. J Phys Chem B 2010; 114:13839-46. [DOI: 10.1021/jp103547s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Yubo Zhang
- Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, Institut de Biologie Physico-Chimique, Laboratoire de Biochimie Théorique, CNRS UPR 9080, 13, rue Pierre et Marie Curie, F-75005 Paris, France, and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Marc Baaden
- Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, Institut de Biologie Physico-Chimique, Laboratoire de Biochimie Théorique, CNRS UPR 9080, 13, rue Pierre et Marie Curie, F-75005 Paris, France, and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Junjie Yan
- Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, Institut de Biologie Physico-Chimique, Laboratoire de Biochimie Théorique, CNRS UPR 9080, 13, rue Pierre et Marie Curie, F-75005 Paris, France, and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Jinzhen Shao
- Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, Institut de Biologie Physico-Chimique, Laboratoire de Biochimie Théorique, CNRS UPR 9080, 13, rue Pierre et Marie Curie, F-75005 Paris, France, and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Su Qiu
- Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, Institut de Biologie Physico-Chimique, Laboratoire de Biochimie Théorique, CNRS UPR 9080, 13, rue Pierre et Marie Curie, F-75005 Paris, France, and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Yingliang Wu
- Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, Institut de Biologie Physico-Chimique, Laboratoire de Biochimie Théorique, CNRS UPR 9080, 13, rue Pierre et Marie Curie, F-75005 Paris, France, and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
| | - Yi Ding
- Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, Institut de Biologie Physico-Chimique, Laboratoire de Biochimie Théorique, CNRS UPR 9080, 13, rue Pierre et Marie Curie, F-75005 Paris, France, and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China
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Yan Q, Murphy-Ullrich JE, Song Y. Structural insight into the role of thrombospondin-1 binding to calreticulin in calreticulin-induced focal adhesion disassembly. Biochemistry 2010; 49:3685-94. [PMID: 20337411 DOI: 10.1021/bi902067f] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Thrombospondin-1 (TSP1) binding to calreticulin (CRT) on the cell surface stimulates association of CRT with LDL receptor-related protein (LRP1) to signal focal adhesion disassembly and engagement of cellular activities. The structural basis for this phenomenon is unknown. We studied the binding thermodynamics of the TSP1-CRT complex and the conformational changes in CRT induced by binding to TSP1 with combined binding free energy analysis, molecular dynamics simulation, and anisotropic network model restrained molecular dynamics simulation. Results showed that mutations of Lys 24 and Lys 32 in TSP1 to Ala and of amino acids 24-26 and 32-34 in CRT to Ala significantly weakened the binding of TSP1 and CRT, which is consistent with experimental results. Upon validation of the calculated binding affinity changes of the TSP1-CRT complex by mutations in key residues in TSP1 and CRT with the experimental results, we performed conformational analyses to understand the role of TSP1 binding to CRT in the induction of conformational changes in CRT. Conformational analyses showed that TSP1 binding to CRT resulted in a more "open" conformation and a significant rotational change for the CRT N-domain with respect to the CRT P-domain, which could expose the potential binding site(s) in CRT for binding to LRP1 to signal focal adhesion disassembly. Results offer structural insight into the role of TSP1 binding to CRT in CRT-induced focal adhesion disassembly.
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Affiliation(s)
- Qi Yan
- Department of Biomedical Engineering, The University of Alabama at Birmingham,Birmingham, Alabama 35294, USA
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38
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Han S, Yin S, Yi H, Mouhat S, Qiu S, Cao Z, Sabatier JM, Wu Y, Li W. Protein−Protein Recognition Control by Modulating Electrostatic Interactions. J Proteome Res 2010; 9:3118-25. [DOI: 10.1021/pr100027k] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Song Han
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Shijin Yin
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Hong Yi
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Stéphanie Mouhat
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Su Qiu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Jean-Marc Sabatier
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, P. R. China, and ERT 62 ≪Ingénierie des peptides à visée thérapeutique≫, Université de la Méditerranée - Ambrilia Biopharma S.A., Faculté de Médecine Nord, Boulevard Pierre Dramard, 13916 Marseille Cédex 20, France
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Chen PC, Kuyucak S. Mechanism and energetics of charybdotoxin unbinding from a potassium channel from molecular dynamics simulations. Biophys J 2009; 96:2577-88. [PMID: 19348743 DOI: 10.1016/j.bpj.2008.12.3952] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 12/10/2008] [Accepted: 12/15/2008] [Indexed: 10/20/2022] Open
Abstract
Ion channel-toxin complexes are ideal systems for computational studies of protein-ligand interactions, because, in most cases, the channel axis provides a natural reaction coordinate for unbinding of a ligand and a wealth of physiological data is available to check the computational results. We use a recently determined structure of a potassium channel-charybdotoxin complex in molecular dynamics simulations to investigate the mechanism and energetics of unbinding. Pairs of residues on the channel protein and charybdotoxin that are involved in the binding are identified, and their behavior is traced during umbrella-sampling simulations as charybdotoxin is moved away from the binding site. The potential of mean force for the unbinding of charybdotoxin is constructed from the umbrella sampling simulations using the weighted histogram analysis method, and barriers observed are correlated with specific breaking of interactions and influx of water molecules into the binding site. Charybdotoxin is found to undergo conformational changes as a result of the reaction coordinate choice--a nontrivial decision for larger ligands--which we explore in detail, and for which we propose solutions. Agreement between the calculated and the experimental binding energies is obtained once the energetic consequences of these conformational changes are included in the calculations.
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Affiliation(s)
- Po-Chia Chen
- School of Physics, University of Sydney, Australia
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40
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Qiu S, Yi H, Liu H, Cao Z, Wu Y, Li W. Molecular Information of Charybdotoxin Blockade in the Large Conductance Calcium-activated Potassium Channel. J Chem Inf Model 2009; 49:1831-8. [DOI: 10.1021/ci900025n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Su Qiu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
| | - Hong Yi
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
| | - Hui Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, PR China
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41
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Yin SJ, Jiang L, Yi H, Han S, Yang DW, Liu ML, Liu H, Cao ZJ, Wu YL, Li WX. Different Residues in Channel Turret Determining the Selectivity of ADWX-1 Inhibitor Peptide between Kv1.1 and Kv1.3 Channels. J Proteome Res 2008; 7:4890-7. [DOI: 10.1021/pr800494a] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Shi-Jin Yin
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Ling Jiang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Hong Yi
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Song Han
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Dai-Wen Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Mai-Li Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Hui Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Zhi-Jian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Ying-Liang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
| | - Wen-Xin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China, and Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543
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Corzo G, Papp F, Varga Z, Barraza O, Espino-Solis PG, Rodríguez de la Vega RC, Gaspar R, Panyi G, Possani LD. A selective blocker of Kv1.2 and Kv1.3 potassium channels from the venom of the scorpion Centruroides suffusus suffusus. Biochem Pharmacol 2008; 76:1142-54. [DOI: 10.1016/j.bcp.2008.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 07/29/2008] [Accepted: 08/04/2008] [Indexed: 11/30/2022]
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43
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Conformation and free energy analyses of the complex of calcium-bound calmodulin and the Fas death domain. Biophys J 2008; 95:5913-21. [PMID: 18820240 DOI: 10.1529/biophysj.108.130542] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Previous studies have demonstrated a calcium-dependent interaction of calmodulin (CaM) and Fas that is regulated during Fas-induced apoptosis in several cell lines, including cholangiocarcinoma, Jurkat cells, and osteoclasts. The binding of CaM and Fas has been identified on residues 231-254 of Fas; the V254N point mutation decreases the CaM/Fas binding, and the C-terminal deletion mutation increases the CaM/Fas binding. Recent studies have shown that CaM is recruited into the Fas-mediated death-inducing signaling complex (DISC) in a calcium-dependent manner. However, the molecular mechanisms whereby Fas mutations and CaM/Fas binding might regulate Fas-mediated DISC formation are unknown. In this study we investigated the binding thermodynamics and conformation of the CaM/Fas complexes with combined explicit solvent molecular-dynamics simulations and implicit solvent binding free-energy calculations. The binding free-energy analysis demonstrated that the Fas V254N point mutation reduced its binding affinity with CaM. In contrast, the Fas mutant with the deletion of the 15 amino acid at the C-terminus increased its binding to CaM. These observations are consistent with previous findings from biochemical studies. Conformational analyses further showed that the Fas V254N mutation resulted in an unstable conformation, whereas the C-terminal deletion mutation stabilized the Fas conformation, and both mutations resulted in changes of the degree of correlation between the motions of the residues in Fas. Analysis of the CaM/Fas complex revealed that CaM/Fas binding stabilized the conformation of both CaM and Fas and changed the degree of correlated motion of the residues of CaM and Fas. The results presented here provide structural evidence for the roles of Fas mutations and CaM/Fas binding in Fas-induced DISC formation. Understanding the molecular mechanisms of CaM/Fas binding in Fas-mediated DISC formation should provide important insights into the function of Fas mutations and CaM in regulating Fas-mediated apoptosis.
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Shijin Y, Hong Y, Yibao M, Zongyun C, Han S, Yingliang W, Zhijian C, Wenxin L. Characterization of a new Kv1.3 channel-specific blocker, J123, from the scorpion Buthus martensii Karsch. Peptides 2008; 29:1514-20. [PMID: 18571286 DOI: 10.1016/j.peptides.2008.04.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 04/29/2008] [Accepted: 04/30/2008] [Indexed: 01/22/2023]
Abstract
The potassium channel Kv1.3 is an attractive pharmacological target for T-cell-mediated autoimmune diseases, and specific and selective peptidic blockers of Kv1.3 channels have served as valuable therapeutic leads for treating these diseases. Here, we found a new peptide toxin, J123, with 43 amino acids including six cysteine residues by screening the venomous cDNA library of scorpion Buthus martensii Karsch, which has been used as traditional medicine in China for more than 2000 years. The sequence analysis suggested that peptide J123 constituted a new member of the alpha-KTx toxins. The electrophysiological experiments further indicated that peptide J123 has a novel pharmacological profiles: it blocked Kv1.3 channel with high potency (IC50=0.79 nM), and exhibited good selectivity on Kv1.3 over Kv1.1 (>1000-fold) and Kv1.2 (about 30-fold), respectively. Furthermore, peptide J123 had no activity on SKCa2 and SKCa3 channels at micromolar concentration level. Based on the pharmacological activities, the possible channel-interacting surface of peptide J123 was also predicted by molecular modeling and docking. All these data not only enrich the knowledge of the structure-function relationship of the new Kv1.3-speicific peptide but also present a potential drug candidate for selectively targeting Kv1.3 channels.
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Affiliation(s)
- Yin Shijin
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, PR China
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Han S, Yi H, Yin SJ, Chen ZY, Liu H, Cao ZJ, Wu YL, Li WX. Structural Basis of a Potent Peptide Inhibitor Designed for Kv1.3 Channel, a Therapeutic Target of Autoimmune Disease. J Biol Chem 2008; 283:19058-65. [DOI: 10.1074/jbc.m802054200] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Gan G, Yi H, Chen M, Sun L, Li W, Wu Y, Ding J. Structural basis for toxin resistance of beta4-associated calcium-activated potassium (BK) channels. J Biol Chem 2008; 283:24177-84. [PMID: 18559348 DOI: 10.1074/jbc.m800179200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The functional diversity of large conductance Ca(2+)- and voltage-dependent K(+) (BK) channels arises mainly from co-assembly of the pore-forming mSlo alpha subunits with four tissue-enriched auxiliary beta subunits. The structural basis of the interaction between alpha subunits with beta subunits is not well understood. Using computational and experimental methods, we demonstrated that four mSlo turrets decentralized distally from the channel pore to provide a wide open conformation and that the mSlo and hbeta4 subunits together formed a "helmet" containing three basic residues (Lys-120, Arg-121, and Lys-125), which impeded the entry of charybdotoxin (ChTX) by both the electrostatic interaction and limited space. In addition, the tyrosine insert mutant (in100Y) showed 56% inhibition, with a K(d) = 17 nm, suggesting that the hbeta4 lacks an external ChTX-binding site (Tyr-100). We also found that mSlo had an internal binding site (Tyr-294) in the alpha subunits that could "permanently" block 15% of mSlo+hbeta4 currents in the presence of 100 nm ChTX. These findings provide a better understanding of the diverse interactions between alpha and beta subunits and will improve the design of channel inhibitors.
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Affiliation(s)
- Geliang Gan
- Key Laboratory of Molecular Biophysics (Huazhong University of Science and Technology) Ministry of Education, College of Life Science and Technology, Wuhan, Hubei, China
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