1
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Tumba NL, Owen GR, Killick MA, Papathanasopoulos MA. Immunization with HIV-1 trimeric SOSIP.664 BG505 or Founder Virus C (FVCEnv) covalently complexed to two-domain CD4S60C elicits cross-clade neutralizing antibodies in New Zealand white rabbits. Vaccine X 2022; 12:100222. [PMID: 36262212 PMCID: PMC9573916 DOI: 10.1016/j.jvacx.2022.100222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 09/21/2022] [Accepted: 09/28/2022] [Indexed: 11/22/2022] Open
Abstract
Background: An ongoing challenge in HIV-1 vaccine research is finding a novel HIV-1 envelope glycoprotein (Env)-based immunogen that elicits broadly cross-neutralizing antibodies (bnAbs) without requiring complex sequential immunization regimens to drive the required antibody affinity maturation. Previous vaccination studies have shown monomeric Env and Env trimers which contain the GCN4 leucine zipper trimerization domain and are covalently bound to the first two domains of CD4 (2dCD4S60C) generate potent bnAbs in small animals. Since SOSIP.664 trimers are considered the most accurate, conformationally intact representation of HIV-1 Env generated to date, this study further evaluated the immunogenicity of SOSIP.664 HIV Env trimers (the well characterized BG505 and FVCEnv) covalently complexed to 2dCD4S60C. Methods: Recombinant BG505 SOSIP.664 and FVCEnv SOSIP.664 were expressed in mammalian cells, purified, covalently coupled to 2dCD4S60C and antigenically characterized for their interaction with HIV-1 bnAbs. The immunogenicity of BG505 SOSIP.664-2dCD4S60C and FVCEnv SOSIP.664-2dCD4S60C was investigated in New Zealand white rabbits and compared to unliganded FVCEnv and 2dCD4S60C. Rabbit sera were tested for the presence of neutralizing antibodies against a panel of 17 pseudoviruses. Results: Both BG505 SOSIP.664-2dCD4S60C and FVCEnv SOSIP.664-2dCD4S60C elicited a potent, HIV-specific response in rabbits with antibodies having considerable potency and breadth (70.5% and 76%, respectively) when tested against a global panel of 17 pseudoviruses mainly composed of harder-to-neutralize multiple clade tier-2 pseudoviruses. Conclusion: BG505 SOSIP.664-2dCD4S60C and FVCEnvSOSIP.664-2dCD4S60C are highly immunogenic and elicit potent, broadly neutralizing antibodies, the extent of which has never been reported previously for SOSIP.664 trimers. Adding to our previous results, the ability to consistently elicit these types of potent, cross-neutralizing antibody responses is dependent on novel epitopes exposed following the covalent binding of Env (independent of sequence and conformation) to 2dCD4S60C. These findings justify further investment into research exploring modified open, CD4-bound Env conformations as novel vaccine immunogens.
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2
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Fu M, Xiao Y, Du T, Hu H, Ni F, Hu K, Hu Q. Fusion Proteins CLD and CLDmut Demonstrate Potent and Broad Neutralizing Activity against HIV-1. Viruses 2022; 14:v14071365. [PMID: 35891347 PMCID: PMC9323411 DOI: 10.3390/v14071365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
HIV-1 envelope glycoprotein (Env) interacts with cellular receptors and mediates virus entry into target cells. Blocking Env-receptor interactions represents an effective interventional strategy for developing HIV-1 entry inhibitors. We previously designed a panel of CD4-linker-DC-SIGN (CLD) constructs by fusing the extracellular CD4 and DC-SIGN domains with various linkers. Such CLDs produced by the prokaryotic system efficiently inhibited HIV-1 infection and dissemination in vitro and ex vivo. In this study, following the construction and identification of the most promising candidate with a linker of 8 Gly4Ser repeats (named CLD), we further designed an improved form (named CLDmut) by back mutating Cys to Ser at amino acid 60 of CD4. Both CLD and CLDmut were produced in mammalian (293F) cells for better protein translation and modification. The anti-HIV-1 activity of CLD and CLDmut was assessed against the infection of a range of HIV-1 isolates, including transmitted and founder (T/F) viruses. While both CLD and CLDmut efficiently neutralized the tested HIV-1 isolates, CLDmut demonstrated much higher neutralizing activity than CLD, with an IC50 up to one log lower. The neutralizing activity of CLDmut was close to or more potent than those of the highly effective HIV-1 broadly neutralizing antibodies (bNAbs) reported to date. Findings in this study indicate that mammalian cell-expressed CLDmut may have the potential to be used as prophylaxis or/and therapeutics against HIV-1 infection.
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Affiliation(s)
- Ming Fu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; (M.F.); (Y.X.); (T.D.); (H.H.); (F.N.); (K.H.)
| | - Yingying Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; (M.F.); (Y.X.); (T.D.); (H.H.); (F.N.); (K.H.)
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tao Du
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; (M.F.); (Y.X.); (T.D.); (H.H.); (F.N.); (K.H.)
| | - Huimin Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; (M.F.); (Y.X.); (T.D.); (H.H.); (F.N.); (K.H.)
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fengfeng Ni
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; (M.F.); (Y.X.); (T.D.); (H.H.); (F.N.); (K.H.)
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; (M.F.); (Y.X.); (T.D.); (H.H.); (F.N.); (K.H.)
| | - Qinxue Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China; (M.F.); (Y.X.); (T.D.); (H.H.); (F.N.); (K.H.)
- Institute for Infection and Immunity, St George’s, University of London, London SW17 0RE, UK
- Correspondence: ; Tel.: +86-27-8719-9992
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3
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PIF - A Java library for finding atomic interactions and extracting geometric features supporting the analysis of protein structures. Methods 2022; 205:63-72. [PMID: 35724844 DOI: 10.1016/j.ymeth.2022.04.018] [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: 02/06/2022] [Revised: 03/13/2022] [Accepted: 04/16/2022] [Indexed: 11/22/2022] Open
Abstract
Proteins play an essential role in the functioning of living organisms. The enormity of the atomic interactions in proteins is essential in controlling their spatial structures and dynamics. It can also provide scientists with valuable information that help to determine the native structures of proteins. This paper presents the PIF (Protein Interaction Finder) library for the Java language, enabling the identification of selected atomic interactions (hydrogen and disulfide bonds, ionic, hydrophobic, aromatic-aromatic, sulfur-aromatic, and amino-aromatic interactions) based on the three-dimensional structure of proteins. The interaction calculation rules applied in PIF rely on documented theoretical foundations gathered from experimental studies of interactions in native protein structures. The library has a universal purpose, supporting drug discovery and development processes and protein structure modeling. Finding the atomic interactions can also deliver numerical features for various Artificial Intelligence (AI) models built for protein analysis. The conducted research comparing the results obtained with the use of the PIF library and competing tools has shown that our solution can effectively determine the interactions occurring in protein structures for entire collections of proteins. Moreover, as a solution that provides a programming interface, the PIF library can be used in any Java project, making it a universal tool.
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4
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Meirson T, Bomze D, Markel G. Structural basis of SARS-CoV-2 spike protein induced by ACE2. Bioinformatics 2021; 37:929-936. [PMID: 32818261 PMCID: PMC7558967 DOI: 10.1093/bioinformatics/btaa744] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/20/2020] [Accepted: 08/14/2020] [Indexed: 12/24/2022] Open
Abstract
Motivation The recent emergence of the novel SARS-coronavirus 2 (SARS-CoV-2) and its international
spread pose a global health emergency. The spike (S) glycoprotein binds ACE2 and
promotes SARS-CoV-2 entry into host cells. The trimeric S protein binds the receptor
using the receptor-binding domain (RBD) causing conformational changes in S protein that
allow priming by host cell proteases. Unraveling the dynamic structural features used by
SARS-CoV-2 for entry might provide insights into viral transmission and reveal novel
therapeutic targets. Using structures determined by X-ray crystallography and cryo-EM,
we performed structural analysis and atomic comparisons of the different conformational
states adopted by the SARS-CoV-2-RBD. Results Here, we determined the key structural components induced by the receptor and
characterized their intramolecular interactions. We show that κ-helix (polyproline-II)
is a predominant structure in the binding interface and in facilitating the conversion
to the active form of the S protein. We demonstrate a series of conversions between
switch-like κ-helix and β-strand, and conformational variations in a set of short
α-helices which affect the hinge region. These conformational changes lead to an
alternating pattern in conserved disulfide bond configurations positioned at the hinge,
indicating a possible disulfide exchange, an important allosteric switch implicated in
viral entry of various viruses, including HIV and murine coronavirus. The structural
information presented herein enables to inspect and understand the important dynamic
features of SARS-CoV-2-RBD and propose a novel potential therapeutic strategy to block
viral entry. Overall, this study provides guidance for the design and optimization of
structure-based intervention strategies that target SARS-CoV-2. Availability We have implemented the proposed methods in an R package freely available at https://github.com/Grantlab/bio3d Supplementary information Supplementary data are
available at Bioinformatics online.
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Affiliation(s)
- Tomer Meirson
- Ella Lemelbaum Institute for Immuno-oncology, Sheba Medical Center, Ramat-Gan 526260, Israel.,The Azrieli Faculty of Medicine, Bar-Ilan University, Safed 1311502, Israel
| | | | - Gal Markel
- Ella Lemelbaum Institute for Immuno-oncology, Sheba Medical Center, Ramat-Gan 526260, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.,Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
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5
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Zhang J, Duan D, Osama A, Fang J. Natural Molecules Targeting Thioredoxin System and Their Therapeutic Potential. Antioxid Redox Signal 2021; 34:1083-1107. [PMID: 33115246 DOI: 10.1089/ars.2020.8213] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Significance: Thioredoxin (Trx) and thioredoxin reductase are two core members of the Trx system. The system bridges the gap between the universal reducing equivalent NADPH and various biological molecules and plays an essential role in maintaining cellular redox homeostasis and regulating multiple cellular redox signaling pathways. Recent Advance: In recent years, the Trx system has been well documented as an important regulator of many diseases, especially tumorigenesis. Thus, the development of potential therapeutic molecules targeting the system is of great significance for disease treatment. Critical Issues: We herein first discuss the physiological functions of the Trx system and the role that the Trx system plays in various diseases. Then, we focus on the introduction of natural small molecules with potential therapeutic applications, especially the anticancer activity, and review their mechanisms of pharmacological actions via interfering with the Trx system. Finally, we further discuss several natural molecules that harbor therapeutic potential and have entered different clinical trials. Future Directions: Further studies on the functions of the Trx system in multiple diseases will not only improve our understanding of the pathogenesis of many human disorders but also help develop novel therapeutic strategies against these diseases. Antioxid. Redox Signal. 34, 1083-1107.
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Affiliation(s)
- Junmin Zhang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, and School of Pharmacy, Lanzhou University, Lanzhou, China
- Shaanxi Key Laboratory of Phytochemistry, Baoji University of Arts and Sciences, Baoji, China
| | - Dongzhu Duan
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, and School of Pharmacy, Lanzhou University, Lanzhou, China
- Shaanxi Key Laboratory of Phytochemistry, Baoji University of Arts and Sciences, Baoji, China
| | - Alsiddig Osama
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, and School of Pharmacy, Lanzhou University, Lanzhou, China
- Shaanxi Key Laboratory of Phytochemistry, Baoji University of Arts and Sciences, Baoji, China
| | - Jianguo Fang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, and School of Pharmacy, Lanzhou University, Lanzhou, China
- Shaanxi Key Laboratory of Phytochemistry, Baoji University of Arts and Sciences, Baoji, China
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6
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Cysteine Residues in Helicobacter pylori Adhesin HopQ are Required for CEACAM-HopQ Interaction and Subsequent CagA Translocation. Microorganisms 2020; 8:microorganisms8040465. [PMID: 32218315 PMCID: PMC7232459 DOI: 10.3390/microorganisms8040465] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/20/2020] [Accepted: 03/24/2020] [Indexed: 12/16/2022] Open
Abstract
Attachment to the host gastric mucosa is a key step in Helicobacter pylori infection. Recently, a novel adhesin, HopQ, was shown to bind distinct host CEACAM proteins—an interaction that was found to be essential for the translocation of CagA, a key virulence factor of H. pylori. The HopQ–CEACAM1 co-crystal structure revealed a binding mode dependent on loops in HopQ that are clasped by disulfide bonds. In this study, we investigated the importance of these cysteine residues for CEACAM1 engagement by H. pylori. We observed a loss of CEACAM1 binding and CagA translocation upon disruption of the disulfide bond in loop CL1 (connecting C103 to C132 in HopQ). Deletion of the Dsb-like oxidoreductase HP0231 did not affect cell surface expression of HopQ or alter the interaction of H. pylori with target cells. Although HP0231 deletion was previously described to impede CagA translocation, our results indicate that this occurs through a HopQ-independent mechanism. Together, our results open up new avenues to therapeutically target the HopQ–CEACAM1 interaction and reduce the burden of pathogenic H. pylori.
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7
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Chiu J, Hogg PJ. Allosteric disulfides: Sophisticated molecular structures enabling flexible protein regulation. J Biol Chem 2019; 294:2949-2960. [PMID: 30635401 DOI: 10.1074/jbc.rev118.005604] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Protein disulfide bonds link pairs of cysteine residues in polypeptide chains. Many of these bonds serve a purely structural or energetic role, but a growing subset of cleavable disulfide bonds has been shown to control the function of the mature protein in which they reside. These allosteric disulfides and the factors that cleave these bonds are being identified across biological systems and life forms and have been shown to control hemostasis, the immune response, and viral infection in mammals. The discovery of these functional disulfides and a rationale for their facile nature has been aided by the emergence of a conformational signature for allosteric bonds. This post-translational modification mostly occurs extracellularly, making these chemical events prime drug targets. Indeed, a membrane-impermeable inhibitor of one of the cleaving factors is currently being trialed as an antithrombotic agent in cancer patients. Allosteric disulfides are firmly established as a sophisticated means by which a protein's shape and function can be altered; however, the full scope of this biological regulation will not be realized without new tools and techniques to study this regulation and innovative ways of targeting it.
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Affiliation(s)
- Joyce Chiu
- From the Centenary Institute, National Health and Medical Research Council Clinical Trials Centre, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2006, Australia
| | - Philip J Hogg
- From the Centenary Institute, National Health and Medical Research Council Clinical Trials Centre, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2006, Australia
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8
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Falkenhagen A, Joshi S. HIV Entry and Its Inhibition by Bifunctional Antiviral Proteins. MOLECULAR THERAPY-NUCLEIC ACIDS 2018; 13:347-364. [PMID: 30340139 PMCID: PMC6197789 DOI: 10.1016/j.omtn.2018.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022]
Abstract
HIV entry is a highly specific and time-sensitive process that can be divided into receptor binding, coreceptor binding, and membrane fusion. Bifunctional antiviral proteins (bAVPs) exploit the multi-step nature of the HIV entry process by binding to two different extracellular targets. They are generated by expressing a fusion protein containing two entry inhibitors with a flexible linker. The resulting fusion proteins exhibit exceptional neutralization potency and broad cross-clade inhibition. In this review, we summarize the HIV entry process and provide an overview of the design, antiviral potency, and methods of delivery of bAVPs. Additionally, we discuss the advantages and limitations of bAVPs for HIV prevention and treatment.
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Affiliation(s)
- Alexander Falkenhagen
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E2, Canada
| | - Sadhna Joshi
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E2, Canada.
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9
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Owen GR, Le D, Stoychev S, Cerutti NM, Papathanasopoulos M. Redox exchange of the disulfides of human two-domain CD4 regulates the conformational dynamics of each domain, providing insight into its mechanisms of control. Biochem Biophys Res Commun 2018; 497:811-817. [PMID: 29470989 DOI: 10.1016/j.bbrc.2018.02.161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 02/18/2018] [Indexed: 11/18/2022]
Abstract
CD4, a membrane glycoprotein expressed by specific leukocytes, plays a vital role in the human immune response and acts as a primary receptor for HIV entry. Of its four ecto-domains (D1-D4), D1, D2, and D4 each contain a distinctive disulfide bond. Whereas the disulfides of D1 and D4 are more traditional in nature, providing structural functions, that of D2 is referred to as an "allosteric" disulfide due to its high dihedral strain energy and relative ease of reduction that is thought to regulate CD4 structure and function by shuffling its redox state. While we have shown previously that elimination of the pre-stressed D2 disulfide results in a favorable structural collapse that increases the stability of a CD4 variant comprising only D1 and D2 (2dCD4), we sought to further localize and determine the nature of the biophysical modifications that take place upon redox exchange of the D1 and D2 disulfides by using amide hydrogen-deuterium exchange mass spectrometry (HDX-MS) to measure induced changes in conformational dynamics. By analyzing various redox isomers of 2dCD4, we demonstrate that ablation of the D1 disulfide enhances the dynamics of the domain considerably, with little effect on that of D2. Reduction of the D2 disulfide however decreases the conformational dynamics of many of the β-strands of the domain that enclose the bond, suggesting a model in which inward collapse of secondary structure occurs around the allosteric disulfide upon its eradication, resulting in a marked decrease in hydrodynamic volume and increase in stability as previously described. Increases in the dynamics of regions important for HIV gp120 and MHCII binding in D1 also result allosterically after reducing the D2 disulfide, which are likely a consequence of the structural changes that take place in D2, findings that advance our understanding of the mechanisms by which redox exchange of the CD4 disulfides regulates its function.
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Affiliation(s)
- Gavin R Owen
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, Johannesburg, South Africa.
| | - Doris Le
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, Johannesburg, South Africa
| | - Stoyan Stoychev
- Council for Scientific and Industrial Research, Biosciences, Pretoria, 0001, South Africa
| | - Nichole M Cerutti
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, Johannesburg, South Africa
| | - Maria Papathanasopoulos
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193, Johannesburg, South Africa
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10
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Owen GR, Channell JA, Forsyth VT, Haertlein M, Mitchell EP, Capovilla A, Papathanasopoulos M, Cerutti NM. Human CD4 Metastability Is a Function of the Allosteric Disulfide Bond in Domain 2. Biochemistry 2016; 55:2227-37. [DOI: 10.1021/acs.biochem.6b00154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gavin R. Owen
- HIV
Pathogenesis Research Unit, Department of Molecular Medicine and Haematology,
Faculty of Health Sciences, University of the Witwatersrand, 7
York Road, Parktown, 2193, Johannesburg, South Africa
| | - Jennifer A. Channell
- Faculty
of Natural Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
- Life
Sciences Group, Institut Laue-Langevin, 71 Avenue des Martyrs, 38042, Grenoble, France
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38042, Grenoble, France
| | - V. Trevor Forsyth
- Faculty
of Natural Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
- Life
Sciences Group, Institut Laue-Langevin, 71 Avenue des Martyrs, 38042, Grenoble, France
| | - Michael Haertlein
- Life
Sciences Group, Institut Laue-Langevin, 71 Avenue des Martyrs, 38042, Grenoble, France
| | - Edward P. Mitchell
- Faculty
of Natural Sciences, Keele University, Keele, Staffordshire ST5 5BG, United Kingdom
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38042, Grenoble, France
| | - Alexio Capovilla
- HIV
Pathogenesis Research Unit, Department of Molecular Medicine and Haematology,
Faculty of Health Sciences, University of the Witwatersrand, 7
York Road, Parktown, 2193, Johannesburg, South Africa
| | - Maria Papathanasopoulos
- HIV
Pathogenesis Research Unit, Department of Molecular Medicine and Haematology,
Faculty of Health Sciences, University of the Witwatersrand, 7
York Road, Parktown, 2193, Johannesburg, South Africa
| | - Nichole M. Cerutti
- HIV
Pathogenesis Research Unit, Department of Molecular Medicine and Haematology,
Faculty of Health Sciences, University of the Witwatersrand, 7
York Road, Parktown, 2193, Johannesburg, South Africa
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11
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Bailey LD, Kalyana Sundaram RV, Li H, Duffy C, Aneja R, Rosemary Bastian A, Holmes AP, Kamanna K, Rashad AA, Chaiken I. Disulfide Sensitivity in the Env Protein Underlies Lytic Inactivation of HIV-1 by Peptide Triazole Thiols. ACS Chem Biol 2015; 10:2861-73. [PMID: 26458166 DOI: 10.1021/acschembio.5b00381] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the mode of action underlying lytic inactivation of HIV-1 virions by peptide triazole thiol (PTT), in particular the relationship between gp120 disulfides and the C-terminal cysteine-SH required for virolysis. Obligate PTT dimer obtained by PTT SH cross-linking and PTTs with serially truncated linkers between pharmacophore isoleucine-ferrocenyltriazole-proline-tryptophan and cysteine-SH were synthesized. PTT variants showed loss of lytic activity but not binding and infection inhibition upon SH blockade. A disproportionate loss of lysis activity vs binding and infection inhibition was observed upon linker truncation. Molecular docking of PTT onto gp120 argued that, with sufficient linker length, the peptide SH could approach and disrupt several alternative gp120 disulfides. Inhibition of lysis by gp120 mAb 2G12, which binds at the base of the V3 loop, as well as disulfide mutational effects, argued that PTT-induced disruption of the gp120 disulfide cluster at the base of the V3 loop is an important step in lytic inactivation of HIV-1. Further, PTT-induced lysis was enhanced after treating virus with reducing agents dithiothreitol and tris (2-carboxyethyl)phosphine. Overall, the results are consistent with the view that the binding of PTT positions the peptide SH group to interfere with conserved disulfides clustered proximal to the CD4 binding site in gp120, leading to disulfide exchange in gp120 and possibly gp41, rearrangement of the Env spike, and ultimately disruption of the viral membrane. The dependence of lysis activity on thiol-disulfide interaction may be related to intrinsic disulfide exchange susceptibility in gp120 that has been reported previously to play a role in HIV-1 cell infection.
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Affiliation(s)
- Lauren D. Bailey
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Ramalingam Venkat Kalyana Sundaram
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
- School
of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Huiyuan Li
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Caitlin Duffy
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Rachna Aneja
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | | | - Andrew P. Holmes
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Kantharaju Kamanna
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Adel A. Rashad
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Irwin Chaiken
- Department
of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
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12
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Killick MA, Grant ML, Cerutti NM, Capovilla A, Papathanasopoulos MA. Env-2dCD4 S60C complexes act as super immunogens and elicit potent, broadly neutralizing antibodies against clinically relevant human immunodeficiency virus type 1 (HIV-1). Vaccine 2015; 33:6298-306. [PMID: 26432912 DOI: 10.1016/j.vaccine.2015.09.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 08/24/2015] [Accepted: 09/16/2015] [Indexed: 11/28/2022]
Abstract
The ability to induce a broadly neutralizing antibody (bNAb) response following vaccination is regarded as a crucial aspect in developing an effective vaccine against human immunodeficiency virus type 1 (HIV-1). The bNAbs target the HIV-1 envelope glycoprotein (Env) which is exposed on the virus surface, thereby preventing cell entry. To date, conventional vaccine approaches such as the use of Env-based immunogens have been unsuccessful. We expressed, purified, characterized and evaluated the immunogenicity of several unique HIV-1 subtype C Env immunogens in small animals. Here we report that vaccine immunogens based on Env liganded to a two domain CD4 variant, 2dCD4(S60C) are capable of consistently eliciting potent, broadly neutralizing antibody responses in New Zealand white rabbits against a panel of clinically relevant HIV-1 pseudoviruses. This was irrespective of the Env protein subtype and context. Importantly, depletion of the anti-CD4 antibodies appeared to abrogate the neutralization activity in the rabbit sera. Taken together, this data suggests that the Env-2dCD4(S60C) complexes described here are "super" immunogens, and potentially immunofocus antibody responses to a unique epitope spanning the 2dCD4(60C). Recent data from the two available anti-CD4 monoclonal antibodies, Ibalizumab and CD4-Ig (and bispecific variants thereof) have highlighted that the use of these broad and potent entry inhibitors could circumvent the need for a conventional vaccine targeting HIV-1. Overall, the ability of the unique Env-2dCD4(S60C) complexes to elicit potent bNAb responses has not been described previously, reinforcing that further investigation for their utility in preventing and controlling HIV-1/SIV infection is warranted.
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Affiliation(s)
- Mark A Killick
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand Medical School, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Michelle L Grant
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand Medical School, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Nichole M Cerutti
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand Medical School, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Alexio Capovilla
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand Medical School, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Maria A Papathanasopoulos
- HIV Pathogenesis Research Unit, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand Medical School, 7 York Road, Parktown, Johannesburg 2193, South Africa.
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13
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Robillard DE, Mpangase PT, Hazelhurst S, Dehne F. SpeeDB: fast structural protein searches. Bioinformatics 2015; 31:3027-34. [PMID: 25979473 DOI: 10.1093/bioinformatics/btv274] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/27/2015] [Indexed: 11/12/2022] Open
Abstract
MOTIVATION Interactions between amino acids are important determinants of the structure, stability and function of proteins. Several tools have been developed for the identification and analysis of such interactions in proteins based on the extensive studies carried out on high-resolution structures from Protein Data Bank (PDB). Although these tools allow users to identify and analyze interactions, analysis can only be performed on one structure at a time. This makes it difficult and time consuming to study the significance of these interactions on a large scale. RESULTS SpeeDB is a web-based tool for the identification of protein structures based on structural properties. SpeeDB queries are executed on all structures in the PDB at once, quickly enough for interactive use. SpeeDB includes standard queries based on published criteria for identifying various structures: disulphide bonds, catalytic triads and aromatic-aromatic, sulphur-aromatic, cation-π and ionic interactions. Users can also construct custom queries in the user interface without any programming. Results can be downloaded in a Comma Separated Value (CSV) format for further analysis with other tools. Case studies presented in this article demonstrate how SpeeDB can be used to answer various biological questions. Analysis of human proteases revealed that disulphide bonds are the predominant type of interaction and are located close to the active site, where they promote substrate specificity. When comparing the two homologous G protein-coupled receptors and the two protein kinase paralogs analyzed, the differences in the types of interactions responsible for stability accounts for the differences in specificity and functionality of the structures. AVAILABILITY AND IMPLEMENTATION SpeeDB is available at http://www.parallelcomputing.ca as a web service. CONTACT d@drobilla.net SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- David E Robillard
- School of Computer Science, Carleton University, Ottawa, Ontario, Canada, Sydney Brenner Institute for Molecular Bioscience and School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, South Africa
| | - Phelelani T Mpangase
- School of Computer Science, Carleton University, Ottawa, Ontario, Canada, Sydney Brenner Institute for Molecular Bioscience and School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, South Africa
| | - Scott Hazelhurst
- School of Computer Science, Carleton University, Ottawa, Ontario, Canada, Sydney Brenner Institute for Molecular Bioscience and School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, South Africa School of Computer Science, Carleton University, Ottawa, Ontario, Canada, Sydney Brenner Institute for Molecular Bioscience and School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, South Africa
| | - Frank Dehne
- School of Computer Science, Carleton University, Ottawa, Ontario, Canada, Sydney Brenner Institute for Molecular Bioscience and School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, South Africa
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14
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Haworth NL, Wouters MA. Cross-strand disulfides in the non-hydrogen bonding site of antiparallel β-sheet (aCSDns): poised for biological switching. RSC Adv 2015. [DOI: 10.1039/c5ra10672a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
aCSDns are forbidden disulfides with protein redox-activity. Within the aCSDn structural motif, a cognate substrate of Trx-like enzymes, the disulfide bonds are strained and metastable, facilitating their role as redox-regulated protein switches.
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Affiliation(s)
- Naomi L. Haworth
- Life and Environmental Sciences
- Deakin University
- Geelong 3217
- Australia
- Victor Chang Cardiac Research Institute
| | - Merridee A. Wouters
- Olivia Newton-John Cancer Research Institute
- Heidelberg 3084
- Australia
- School of Cancer Medicine
- La Trobe University
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15
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Cerutti N, Killick M, Jugnarain V, Papathanasopoulos M, Capovilla A. Disulfide reduction in CD4 domain 1 or 2 is essential for interaction with HIV glycoprotein 120 (gp120), which impairs thioredoxin-driven CD4 dimerization. J Biol Chem 2014; 289:10455-10465. [PMID: 24550395 PMCID: PMC4036167 DOI: 10.1074/jbc.m113.539353] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/12/2014] [Indexed: 11/06/2022] Open
Abstract
Human CD4 is a membrane-bound glycoprotein expressed on the surface of certain leukocytes, where it plays a key role in the activation of immunostimulatory T cells and acts as the primary receptor for human immunodeficiency virus (HIV) glycoprotein (gp120). Although growing evidence suggests that redox exchange reactions involving CD4 disulfides, potentially catalyzed by cell surface-secreted oxidoreductases such as thioredoxin (Trx) and protein disulfide isomerase, play an essential role in regulating the activity of CD4, their mechanism(s) and biological utility remain incompletely understood. To gain more insights in this regard, we generated a panel of recombinant 2-domain CD4 proteins (2dCD4), including wild-type and Cys/Ala variants, and used these to show that while protein disulfide isomerase has little capacity for 2dCD4 reduction, Trx reduces 2dCD4 highly efficiently, catalyzing the formation of conformationally distinct monomeric 2dCD4 isomers, and a stable, disulfide-linked 2dCD4 dimer. Moreover, we show that HIV gp120 is incapable of binding a fully oxidized, monomeric 2dCD4 in which both domain 1 and 2 disulfides are intact, but binds robustly to reduced counterparts that are the ostensible products of Trx-mediated isomerization. Finally, we demonstrate that Trx-driven dimerization of CD4, a process believed to be critical for the establishment of functional MHCII-TCR-CD4 antigen presentation complexes, is impaired when CD4 is bound to gp120. These observations reinforce the importance of cell surface redox activity for HIV entry and posit the intriguing possibility that one of the many pathogenic effects of HIV may be related to gp120-mediated inhibition of oxidoreductive CD4 isomerization.
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Affiliation(s)
- Nichole Cerutti
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of Witwatersrand Medical School, 7 York Road Parktown, 2193 Johannesburg, South Africa
| | - Mark Killick
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of Witwatersrand Medical School, 7 York Road Parktown, 2193 Johannesburg, South Africa
| | - Vinesh Jugnarain
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of Witwatersrand Medical School, 7 York Road Parktown, 2193 Johannesburg, South Africa
| | - Maria Papathanasopoulos
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of Witwatersrand Medical School, 7 York Road Parktown, 2193 Johannesburg, South Africa
| | - Alexio Capovilla
- HIV Pathogenesis Research Laboratory, Department of Molecular Medicine and Haematology, University of Witwatersrand Medical School, 7 York Road Parktown, 2193 Johannesburg, South Africa.
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16
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Gadhe CG, Kothandan G, Cho SJ. Characterization of Binding Mode of the Heterobiaryl gp120 Inhibitor in HIV-1 Entry: A Molecular Docking and Dynamics Simulation Study. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.8.2466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Abstract
Protein action in nature is generally controlled by the amount of protein produced and by chemical modification of the protein, and both are often perturbed in cancer. The amino acid side chains and the peptide and disulphide bonds that bind the polypeptide backbone can be post-translationally modified. Post-translational cleavage or the formation of disulphide bonds are now being identified in cancer-related proteins and it is timely to consider how these allosteric bonds could be targeted for new therapies.
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Affiliation(s)
- Philip J Hogg
- Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney NSW 2052, Australia.
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18
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Abstract
Protein action in nature is largely controlled by the level of expression and by post-translational modifications. Post-translational modifications result in a proteome that is at least two orders of magnitude more diverse than the genome. There are three basic types of post-translational modifications: covalent modification of an amino acid side chain, hydrolytic cleavage or isomerization of a peptide bond, and reductive cleavage of a disulfide bond. This review addresses the modification of disulfide bonds. Protein disulfide bonds perform either a structural or a functional role, and there are two types of functional disulfide: the catalytic and allosteric bonds. The allosteric disulfide bonds control the function of the mature protein in which they reside by triggering a change when they are cleaved. The change can be in ligand binding, substrate hydrolysis, proteolysis, or oligomer formation. The allosteric disulfides are cleaved by oxidoreductases or by thiol/disulfide exchange, and the configurations of the disulfides and the secondary structures that they link share some recurring features. How these bonds are being identified using bioinformatics and experimental screens and what the future holds for this field of research are also discussed.
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Affiliation(s)
- Kristina M Cook
- Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney NSW2052, Australia
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19
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Haworth NL, Wouters MA. Between-strand disulfides: forbidden disulfides linking adjacent β-strands. RSC Adv 2013. [DOI: 10.1039/c3ra42486c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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20
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Bifunctional CD4-DC-SIGN fusion proteins demonstrate enhanced avidity to gp120 and inhibit HIV-1 infection and dissemination. Antimicrob Agents Chemother 2012; 56:4640-9. [PMID: 22687513 DOI: 10.1128/aac.00623-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Early stages of mucosal infection are potential targets for HIV-1 prevention. CD4 is the primary receptor in HIV-1 infection whereas DC-SIGN likely plays an important role in HIV-1 dissemination, particularly during sexual transmission. To test the hypothesis that an inhibitor simultaneously targeting both CD4 and DC-SIGN binding sites on gp120 may provide a potent anti-HIV strategy, we designed constructs by fusing the extracellular CD4 and DC-SIGN domains together with varied arrangements of the lengths of CD4, DC-SIGN and the linker. We expressed, purified and characterized a series of soluble CD4-linker-DC-SIGN (CLD) fusion proteins. Several CLDs, composed of a longer linker and an extra neck domain of DC-SIGN, had enhanced affinity for gp120 as evidenced by molecular-interaction analysis. Furthermore, such CLDs exhibited significantly enhanced neutralization activity against both laboratory-adapted and primary HIV-1 isolates. Moreover, CLDs efficiently inhibited HIV-1 infection in trans via a DC-SIGN-expressing cell line and primary human dendritic cells. This was further strengthened by the results from the human cervical explant model, showing that CLDs potently prevented both localized and disseminated infections. This is the first time that soluble DC-SIGN-based bifunctional proteins have demonstrated anti-HIV potency. Our study provides proof of the concept that targeting both CD4 and DC-SIGN binding sites on gp120 represents a novel antiviral strategy. Given that DC-SIGN binding to gp120 increases exposure of the CD4 binding site and that the soluble forms of CD4 and DC-SIGN occur in vivo, further improvement of CLDs may render them potentially useful in prophylaxis or therapeutics.
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21
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Saha P, Barua B, Bhattacharyya S, Balamurali MM, Schief WR, Baker D, Varadarajan R. Design and characterization of stabilized derivatives of human CD4D12 and CD4D1. Biochemistry 2011; 50:7891-900. [PMID: 21827143 DOI: 10.1021/bi200870r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
CD4 is present on the surface of T-lymphocytes and is the primary cellular receptor for HIV-1. CD4 consists of a cytoplasmic tail, one transmembrane region, and four extracellular domains, D1-D4. A construct consisting of the first two domains of CD4 (CD4D12) is folded and binds gp120 with similar affinity as soluble 4-domain CD4 (sCD4). However, the first domain alone (CD4D1) was previously shown to be largely unfolded and had 3-fold weaker affinity for gp120 when compared to sCD4 [Sharma, D.; et al. (2005) Biochemistry 44, 16192-16202]. We now report the design and characterization of three single-site mutants of CD4D12 (G6A, L51I, and V86L) and one multisite mutant of CD4D1 (G6A/L51I/L5K/F98T). G6A, L51I, and V86L are cavity-filling mutations while L5K and F98T are surface mutations which were introduced to minimize the aggregation of CD4D1 upon removal of the second domain. Two mutations, G6A and V86L in CD4D12 increased the stability and yield of the protein relative to the wild-type protein. The mutant CD4D1 (CD4D1a) with the 4 mutations was folded and more stable compared to the original CD4D1, but both bound gp120 with comparable affinity. In in vitro neutralization assays, both CD4D1a and G6A-CD4D12 were able to neutralize diverse HIV-1 viruses with similar IC(50)s as 4-domain CD4. These stabilized derivatives of human CD4 can be useful starting points for the design of other more complex viral entry inhibitors.
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Affiliation(s)
- Piyali Saha
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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22
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Bastian AR, Kantharaju, McFadden K, Duffy C, Rajagopal S, Contarino MR, Papazoglou E, Chaiken I. Cell-free HIV-1 virucidal action by modified peptide triazole inhibitors of Env gp120. ChemMedChem 2011; 6:1335-9, 1318. [PMID: 21714095 DOI: 10.1002/cmdc.201100177] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/13/2011] [Indexed: 11/06/2022]
Affiliation(s)
- Arangassery R Bastian
- Department of Biochemistry and Molecular Biology, Drexel University, College of Medicine, 245 N 15th Street, New College Building, Room 11305, Philadelphia, PA 19102, USA
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23
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Martin G, Burke B, Thaï R, Dey AK, Combes O, Ramos OHP, Heyd B, Geonnotti AR, Montefiori DC, Kan E, Lian Y, Sun Y, Abache T, Ulmer JB, Madaoui H, Guérois R, Barnett SW, Srivastava IK, Kessler P, Martin L. Stabilization of HIV-1 envelope in the CD4-bound conformation through specific cross-linking of a CD4 mimetic. J Biol Chem 2011; 286:21706-16. [PMID: 21487012 DOI: 10.1074/jbc.m111.232272] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD4 binding on gp120 leads to the exposure of highly conserved regions recognized by the HIV co-receptor CCR5 and by CD4-induced (CD4i) antibodies. A covalent gp120-CD4 complex was shown to elicit CD4i antibody responses in monkeys, which was correlated with control of the HIV virus infection (DeVico, A., Fouts, T., Lewis, G. K., Gallo, R. C., Godfrey, K., Charurat, M., Harris, I., Galmin, L., and Pal, R. (2007) Proc. Natl. Acad. Sci. U.S.A. 104, 17477-17482). Because the inclusion of CD4 in a vaccine formulation should be avoided, due to potential autoimmune reactions, we engineered small sized CD4 mimetics (miniCD4s) that are poorly immunogenic and do not induce anti-CD4 antibodies. We made covalent complexes between such an engineered miniCD4 and gp120 or gp140, through a site-directed coupling reaction. These complexes were recognized by CD4i antibodies as well as by the HIV co-receptor CCR5. In addition, they elicit CD4i antibody responses in rabbits and therefore represent potential vaccine candidates that mimic an important HIV fusion intermediate, without autoimmune hazard.
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Affiliation(s)
- Grégoire Martin
- Commissariat à l'Energie Atomique, iBiTecS, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette F-91191, France
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