1
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Wang C, Xia S, Wang X, Li Y, Wang H, Xiang R, Jiang Q, Lan Q, Liang R, Li Q, Huo S, Lu L, Wang Q, Yu F, Liu K, Jiang S. Supercoiling Structure-Based Design of a Trimeric Coiled-Coil Peptide with High Potency against HIV-1 and Human β-Coronavirus Infection. J Med Chem 2022; 65:2809-2819. [PMID: 33929200 PMCID: PMC8117781 DOI: 10.1021/acs.jmedchem.1c00258] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Indexed: 12/15/2022]
Abstract
Hexameric structure formation through packing of three C-terminal helices and an N-terminal trimeric coiled-coil core has been proposed as a general mechanism of class I enveloped virus entry. In this process, the C-terminal helical repeat (HR2) region of viral membrane fusion proteins becomes transiently exposed and accessible to N-terminal helical repeat (HR1) trimer-based fusion inhibitors. Herein, we describe a mimetic of the HIV-1 gp41 HR1 trimer, N3G, as a promising therapeutic against HIV-1 infection. Surprisingly, we found that in addition to protection against HIV-1 infection, N3G was also highly effective in inhibiting infection of human β-coronaviruses, including MERS-CoV, HCoV-OC43, and SARS-CoV-2, possibly by binding the HR2 region in the spike protein of β-coronaviruses to block their hexameric structure formation. These studies demonstrate the potential utility of anti-HIV-1 HR1 peptides in inhibiting human β-coronavirus infection. Moreover, this strategy could be extended to the design of broad-spectrum antivirals based on the supercoiling structure of peptides.
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Affiliation(s)
- Chao Wang
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Shuai Xia
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Xinling Wang
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Yue Li
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Huan Wang
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Rong Xiang
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Qinwen Jiang
- Key Laboratory of Structure-based Drug Design &
Discovery of the Ministry of Education, Shenyang Pharmaceutical
University, Shenyang 110016, China
| | - Qiaoshuai Lan
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Ruiying Liang
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Qing Li
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Shanshan Huo
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Qian Wang
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
| | - Fei Yu
- Hebei Center for Wildlife Health, College of Life
Sciences, Hebei Agricultural University, Baoding 071001,
China
| | - Keliang Liu
- State Key Laboratory of Toxicology and Medical
Countermeasures, Beijing Institute of Pharmacology and
Toxicology, 27 Tai-Ping Road, Beijing 100850,
China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology
(MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical
Center, Fudan University, 130 Dong An Road, Shanghai 200032,
China
- Lindsley F. Kimball Research Institute,
New York Blood Center, New York, New York 10065,
United States
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2
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Xiao Q, Jones ZB, Hatfield SC, Ashton DS, Dalley NA, Dyer CD, Evangelista JL, Price JL. Structural guidelines for stabilization of α-helical coiled coils via PEG stapling. RSC Chem Biol 2022; 3:1096-1104. [PMID: 36128502 PMCID: PMC9428657 DOI: 10.1039/d1cb00237f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 07/01/2022] [Indexed: 11/24/2022] Open
Abstract
Macrocyclization or stapling is one of the most well-known and generally applicable strategies for enhancing peptide/protein conformational stability and target binding affinity. However, there are limited structure- or sequence-based guidelines for the incorporation of optimal interhelical staples within coiled coils: the location and length of an interhelical staple is either arbitrarily chosen or requires significant optimization. Here we explore the impact of interhelical PEG stapling on the conformational stability and proteolytic resistance of a model disulfide-bound heterodimeric coiled coil. We demonstrate that (1) interhelical PEG staples are more stabilizing when placed farther from an existing disulfide crosslink; (2) e/g′ staples are more stabilizing than f/b′ or b/c′ staples; (3) PEG staples between different positions have different optimal staple lengths; (4) PEG stapling tolerates variation in the structure of the PEG linker and in the mode of conjugation; and (5) the guidelines developed here enable the rational design of a stabilized PEG-stapled HER-2 affibody with enhanced conformational stability and proteolytic resistance. Here we identify key criteria for designing PEG-stapled coiled coils with increased conformational and proteolytic stability.![]()
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Affiliation(s)
- Qiang Xiao
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Zachary B. Jones
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Samantha C. Hatfield
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Dallin S. Ashton
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Nicholas A. Dalley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Cody D. Dyer
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Judah L. Evangelista
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Joshua L. Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
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3
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Adihou H, Gopalakrishnan R, Förster T, Guéret SM, Gasper R, Geschwindner S, Carrillo García C, Karatas H, Pobbati AV, Vazquez-Chantada M, Davey P, Wassvik CM, Pang JKS, Soh BS, Hong W, Chiarparin E, Schade D, Plowright AT, Valeur E, Lemurell M, Grossmann TN, Waldmann H. A protein tertiary structure mimetic modulator of the Hippo signalling pathway. Nat Commun 2020; 11:5425. [PMID: 33110077 PMCID: PMC7591920 DOI: 10.1038/s41467-020-19224-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 09/28/2020] [Indexed: 11/21/2022] Open
Abstract
Transcription factors are key protein effectors in the regulation of gene transcription, and in many cases their activity is regulated via a complex network of protein–protein interactions (PPI). The chemical modulation of transcription factor activity is a long-standing goal in drug discovery but hampered by the difficulties associated with the targeting of PPIs, in particular when extended and flat protein interfaces are involved. Peptidomimetics have been applied to inhibit PPIs, however with variable success, as for certain interfaces the mimicry of a single secondary structure element is insufficient to obtain high binding affinities. Here, we describe the design and characterization of a stabilized protein tertiary structure that acts as an inhibitor of the interaction between the transcription factor TEAD and its co-repressor VGL4, both playing a central role in the Hippo signalling pathway. Modification of the inhibitor with a cell-penetrating entity yielded a cell-permeable proteomimetic that activates cell proliferation via regulation of the Hippo pathway, highlighting the potential of protein tertiary structure mimetics as an emerging class of PPI modulators. Targeting the interaction between transcription factor TEAD and its co-repressor VGL4 is an attractive strategy to chemically modulate Hippo signaling. Here, the authors develop a proteomimetic with stabilized tertiary structure that inhibits the TEAD:VGL4 interaction in vitro and in cells.
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Affiliation(s)
- Hélène Adihou
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.,AstraZeneca-MPI Satellite Unit, Dortmund, Germany
| | - Ranganath Gopalakrishnan
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.,AstraZeneca-MPI Satellite Unit, Dortmund, Germany
| | - Tim Förster
- AstraZeneca-MPI Satellite Unit, Dortmund, Germany
| | - Stéphanie M Guéret
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.,AstraZeneca-MPI Satellite Unit, Dortmund, Germany
| | - Raphael Gasper
- Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Stefan Geschwindner
- Structure & Biophysics, Discovery Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - Carmen Carrillo García
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Hacer Karatas
- Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Ajaybabu V Pobbati
- Department of Multi-Modal Molecular (M3) Biology, A*STAR Institute of Molecular and Cell Biology, Singapore, Singapore
| | | | - Paul Davey
- Medicinal Chemistry, Oncology R&D, AstraZeneca, Cambridge, UK
| | - Carola M Wassvik
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Jeremy Kah Sheng Pang
- Disease Modelling and Therapeutics Laboratory, A*STAR Institute of Molecular and Cell Biology, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Boon Seng Soh
- Disease Modelling and Therapeutics Laboratory, A*STAR Institute of Molecular and Cell Biology, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore.,Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Wanjin Hong
- Department of Multi-Modal Molecular (M3) Biology, A*STAR Institute of Molecular and Cell Biology, Singapore, Singapore
| | | | - Dennis Schade
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Alleyn T Plowright
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Eric Valeur
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Malin Lemurell
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Tom N Grossmann
- Department of Chemistry and Pharmaceutical Sciences, VU University Amsterdam, Amsterdam, Netherlands. .,Amsterdam Institute of Molecular and Life Sciences (AIMMS), VU University Amsterdam, Amsterdam, Netherlands.
| | - Herbert Waldmann
- Max Planck Institute for Molecular Physiology, Dortmund, Germany. .,Department of Chemistry and Chemical Biology, Technical University Dortmund, Dortmund, Germany.
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4
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Xiao Q, Ashton DS, Jones ZB, Thompson KP, Price JL. Long-range PEG Stapling: Macrocyclization for Increased Protein Conformational Stability and Resistance to Proteolysis. RSC Chem Biol 2020; 1:273-280. [PMID: 33796855 PMCID: PMC8009319 DOI: 10.1039/d0cb00075b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We previously showed that long-range stapling of two Asn-linked O-allyl PEG oligomers via olefin metathesis substantially increases the conformational stability of the WW domain through an entropic effect. The impact of stapling was more favorable when the staple connected positions that were far apart in primary sequence but close in the folded tertiary structure. Here we validate these criteria by identifying new stabilizing PEG-stapling sites within the WW domain and the SH3 domain, both β-sheet proteins. We find that stapling via olefin metathesis vs. the copper(i)-catalyzed azide/alkyne cycloaddition (CuAAC) results in similar energetic benefits, suggesting that olefin and triazole staples can be used interchangeably. Proteolysis assays of selected WW variants reveal that the observed staple-based increases in conformational stability lead to enhanced proteolytic resistance. Finally, we find that an intermolecular staple dramatically increases the quaternary structural stability of an α-helical GCN4 coiled-coil heterodimer. Long-range stapling of two Asn-linked PEG oligomers via olefin metathesis substantially increases the conformational stability of the WW and SH3 domain tertiary structures and the GCN4 coiled-coil quaternary structure.![]()
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Affiliation(s)
- Qiang Xiao
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Dallin S Ashton
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Zachary B Jones
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Katherine P Thompson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
| | - Joshua L Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, United States
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5
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Horne WS, Grossmann TN. Proteomimetics as protein-inspired scaffolds with defined tertiary folding patterns. Nat Chem 2020; 12:331-337. [PMID: 32029906 DOI: 10.1038/s41557-020-0420-9] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/09/2020] [Indexed: 12/29/2022]
Abstract
Proteins have evolved as a variable platform that provides access to molecules with diverse shapes, sizes and functions. These features have inspired chemists for decades to seek artificial mimetics of proteins with improved or novel properties. Such work has focused primarily on small protein fragments, often isolated secondary structures; however, there has lately been a growing interest in the design of artificial molecules that mimic larger, more complex tertiary folds. In this Perspective, we define these agents as 'proteomimetics' and discuss the recent advances in the field. Proteomimetics can be divided into three categories: protein domains with side-chain functionality that alters the native linear-chain topology; protein domains in which the chemical composition of the polypeptide backbone has been partially altered; and protein-like folded architectures that are composed entirely of non-natural monomer units. We give an overview of these proteomimetic approaches and outline remaining challenges facing the field.
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Affiliation(s)
- W Seth Horne
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Tom N Grossmann
- Department of Chemistry and Pharmaceutical Sciences, VU University Amsterdam, Amsterdam, the Netherlands.
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6
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Lai W, Wang C, Yan J, Liu H, Zhang W, Lin B, Xi Z. Suitable fusion of N-terminal heptad repeats to achieve covalently stabilized potent N-peptide inhibitors of HIV-1 infection. Bioorg Med Chem 2019; 28:115214. [PMID: 31932193 DOI: 10.1016/j.bmc.2019.115214] [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: 09/23/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 10/25/2022]
Abstract
N-terminal heptad repeat (NHR)-derived peptide (N-peptide) fusion inhibitors, which are derived from human immunodeficiency virus (HIV) envelope glycoprotein 41 (gp41), are limited by aggregation and unstable trimer conformation. However, they could function as potent inhibitors of viral infection by forming a coiled-coil structure covalently stabilized by interchain disulfide bonds. We previously synthesized N-peptides with potent anti-HIV-1 activity and high stability by coiled-coil fusion and covalent stabilization. Here, we attempted to study the effects of NHRs of chimeric N-peptides by fusing de novo coiled-coil isopeptide bridge-tethered T21 peptides of different NHR lengths. Peptides (T21N23)3 and (T21N36)3 was a more potent HIV-1 fusion inhibitor than (T21N17)3. The site of isopeptide bond formation was precisely controlled and had little influence on N-peptide properties. The N-peptide (T21N36)3, which had a similar conformation as the NHR trimer and interacted well with the C34 peptide, may be useful for screening other C-peptides and small-molecule fusion inhibitors, and for studying the interactions between the NHR trimer and C-terminal heptad repeats.
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Affiliation(s)
- Wenqing Lai
- Institute of Environmental and Operational Medicine, 1 Da-Li Road, Tianjin 300050, China; Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100089, China
| | - Chao Wang
- Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100089, China
| | - Jun Yan
- Institute of Environmental and Operational Medicine, 1 Da-Li Road, Tianjin 300050, China
| | - Huanliang Liu
- Institute of Environmental and Operational Medicine, 1 Da-Li Road, Tianjin 300050, China
| | - Wei Zhang
- Institute of Environmental and Operational Medicine, 1 Da-Li Road, Tianjin 300050, China
| | - Bencheng Lin
- Institute of Environmental and Operational Medicine, 1 Da-Li Road, Tianjin 300050, China.
| | - Zhuge Xi
- Institute of Environmental and Operational Medicine, 1 Da-Li Road, Tianjin 300050, China.
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7
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Meng G, Pu J, Li Y, Han A, Tian Y, Xu W, Zhang T, Li X, Lu L, Wang C, Jiang S, Liu K. Design and Biological Evaluation of m-Xylene Thioether-Stapled Short Helical Peptides Targeting the HIV-1 gp41 Hexameric Coiled-Coil Fusion Complex. J Med Chem 2019; 62:8773-8783. [PMID: 31513410 DOI: 10.1021/acs.jmedchem.9b00882] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Short peptide-based inhibition of fusion remains an attractive goal in antihuman immunodeficiency virus (HIV) research based on its potential for the development of technically and economically desirable antiviral agents. Herein, we report the use of the dithiol bisalkylation reaction to generate a series of m-xylene thioether-stapled 22-residue α-helical peptides that have been identified as fusion inhibitors targeting HIV-1 glycoprotein 41 (gp41). The peptide sequence is based on the helix-zone binding domain of the gp41 C-terminal heptad repeat region. We found that one of these stapled peptides, named hCS6ERE, showed promising inhibitory potency against HIV-1 Env-mediated cell-cell fusion and viral replication at a level comparable to the clinically used 36-mer peptide T20. Furthermore, combining hCS6ERE with a fusion inhibitor having a different target site, such as HP23, produced synergistic anti-HIV-1 activity. Collectively, our study offers new insight into the design of anti-HIV peptides with short sequences.
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Affiliation(s)
- Guangpeng Meng
- Key Laboratory of Structure-Based Drug Design & Discovery of the Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Jing Pu
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China
| | - Yue Li
- Key Laboratory of Structure-Based Drug Design & Discovery of the Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Aixin Han
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Yangli Tian
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Wei Xu
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China
| | - Tianhong Zhang
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Xue Li
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China
| | - Chao Wang
- State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of (MOE/NHC/CAMS), School of Basic Medical Sciences & Shanghai Public Health Clinical Center , Fudan University , 131 Dong An Road , Shanghai 200032 , China.,Lindsley F. Kimball Research Institute , New York Blood Center , 310 East 67th Street , New York , New York 10065 , United States
| | - Keliang Liu
- Key Laboratory of Structure-Based Drug Design & Discovery of the Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China.,State Key Laboratory of Toxicology and Medical Countermeasures , Beijing Institute of Pharmacology and Toxicology , 27 Tai-Ping Road , Beijing 100850 , China
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8
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Abstract
OBJECTIVE The peptide drug T20 (enfuvirtide), derived from the C-terminal heptad repeat region of HIV-1 gp41, is the only membrane fusion inhibitor available for treatment of viral infection; however, its mechanism of action remains elusive and its structural basis is lacking. DESIGN We focused on determining the crystal structure of T20 in complex with N39, a target mimic peptide derived from the N-terminal heptad repeat region of gp41. On the basis of the structural information, the mechanisms of action of T20 and its resistance were further characterized. METHODS A panel of peptides was synthesized. The T20/N39 complex was assembled for crystallization studies. Circular dichroism spectroscopy, isothermal titration calorimetry (ITC), native polyacrylamide gel electrophoresis (N-PAGE), and mutational analysis were applied to analyze the structural and functional properties. RESULTS A crystal structure of six-helical bundle (6-HB) structure formed by T20 and N39 was determined with a resolution limit of 2.3 Å, which revealed the critical intrahelical and interhelical interactions underlying the mechanism of action of T20 and its resistance mutations. Although the structural properties in the C-terminal tryptophan-rich motif (TRM) of T20 and the fusion peptide proximal region (FPPR) of N39 could not be finely defined by the structure, the data from biophysical and mutational analyses verified the essential roles of the TRM and FPPR motifs for the binding and inhibitory activities of T20. CONCLUSION For the first time, our studies provide a structural basis of T20, which help our understanding on the mechanisms of HIV-1 fusion and its inhibition.
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