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An optimally constrained V3 peptide is a better immunogen than its linear homolog or HIV-1 gp120. Virology 2010; 401:293-304. [PMID: 20347111 DOI: 10.1016/j.virol.2010.03.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 01/12/2010] [Accepted: 03/01/2010] [Indexed: 11/20/2022]
Abstract
Synthetic peptides offer an attractive option for development of a V3-directed vaccine. However, immunization with flexible linear peptides may result in an immune response to multiple conformations, many of which differ from the native conformation of the corresponding region in the protein. Here we show that optimization of the location of a disulfide bond in peptides constrained to mimic the beta-hairpin conformation of the V3, yields an immunogen that elicits a 30-fold stronger HIV-1 neutralizing response in rabbits compared with the homologous linear V3 peptide. The HIV-1 neutralizing response elicited by the optimally constrained peptide is also significantly stronger than that elicited by a gp120 construct in which the V3 is exposed. Neutralization of an HIV-1 strain that shares only 72% identity with the immunizing peptide was demonstrated. The most effective immunogen was also able to neutralize primary isolates that are more resistant to neutralization such as SS1196 and 6535.
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2
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Mor A, Segal E, Mester B, Arshava B, Rosen O, Ding FX, Russo J, Dafni A, Schvartzman F, Scherf T, Naider F, Anglister J. Mimicking the structure of the V3 epitope bound to HIV-1 neutralizing antibodies. Biochemistry 2009; 48:3288-303. [PMID: 19281264 DOI: 10.1021/bi802308n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The third variable region (V3) of the HIV-1 envelope glycoprotein gp120 is a target for virus neutralizing antibodies. The V3 sequence determines whether the virus will manifest R5 or X4 phenotypes and use the CCR5 or CXCR4 chemokine coreceptor, respectively. Previous NMR studies revealed that both R5- and X4-V3 peptides bound to antibodies 0.5beta and 447-52D form beta-hairpin conformations with the GPGR segment at the turn. In contrast, in their free form, linear V3 peptides and a cyclic peptide consisting of the entire 35-residue V3 loop were highly unstructured in aqueous solution. Herein we evaluated a series of synthetic disulfide constrained V3-peptides in which the position of the disulfide bonds, and therefore the ring size, was systematically varied. NMR structures determined for singly and doubly disulfide constrained V3-peptides in aqueous solution were compared with those found for unconstrained V3(JRFL) and V3(IIIB) peptides bound to 447-52D and to 0.5beta, respectively. Our study indicated that cyclic V3 peptides manifested significantly reduced conformational space compared to their linear homologues and that in all cases cyclic peptides exhibited cross-strand interactions suggestive of beta-hairpin-like structures. Nevertheless, the singly constrained V3-peptides retained significant flexibility and did not form an idealized beta-hairpin. Incorporation of a second disulfide bond results in significant overall rigidity, and in one case, a structure close to that of V3(MN) peptide bound to 447-52D Fab was assumed and in another case a structure close to that formed by the linear V3(IIIB) peptide bound to antibody 0.5beta was assumed.
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Affiliation(s)
- Amit Mor
- Department of Structural Biology and Chemical Research Support Weizmann Institute of Science, Rehovot 76100, Israel
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3
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Stanfield RL, Gorny MK, Zolla-Pazner S, Wilson IA. Crystal structures of human immunodeficiency virus type 1 (HIV-1) neutralizing antibody 2219 in complex with three different V3 peptides reveal a new binding mode for HIV-1 cross-reactivity. J Virol 2006; 80:6093-105. [PMID: 16731948 PMCID: PMC1472588 DOI: 10.1128/jvi.00205-06] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human monoclonal antibody 2219 is a neutralizing antibody isolated from a human immunodeficiency virus type 1-infected individual. 2219 was originally selected for binding to a V3 fusion protein and can neutralize primary isolates from subtypes B, A, and F. Thus, 2219 represents a cross-reactive, human anti-V3 antibody. Fab 2219 binds to one face of the variable V3 beta-hairpin, primarily contacting conserved residues on the N-terminal beta-strand of V3, leaving the V3 crown or tip largely accessible. Three V3/2219 complexes reveal the antibody-bound conformations for both the N- and C-terminal regions that flank the V3 crown and illustrate how twisting of the V3 loop alters the relative dispositions and pairing of the amino acids in the adjacent V3 beta-strands and how the antibody can accommodate V3 loops with different sequences.
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Affiliation(s)
- Robyn L Stanfield
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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4
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Haynes BF, Ma B, Montefiori DC, Wrin T, Petropoulos CJ, Sutherland LL, Scearce RM, Denton C, Xia SM, Korber BT, Liao HX. Analysis of HIV-1 subtype B third variable region peptide motifs for induction of neutralizing antibodies against HIV-1 primary isolates. Virology 2005; 345:44-55. [PMID: 16242749 DOI: 10.1016/j.virol.2005.08.042] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 07/14/2005] [Accepted: 08/22/2005] [Indexed: 11/28/2022]
Abstract
The HIV-1 gp120 V3 loop is a potent inducer of neutralizing antibodies for T cell line adapted-HIV-1, but less so for primary isolates. We hypothesized that peptides representative of the diversity of natural HIV-1 V3 loop variants might capture elements of conserved higher order structures and so stimulate broadly reactive neutralizing antibodies. We designed a panel of 29 subtype B V3 sequences postulated to reflect the range of V3 diversity. These peptides were used to immunize guinea pigs. The most effective peptide (62.19) clustered around the subtype B consensus sequence and induced antibodies that reproducibly neutralized 31% of the subtype B HIV-1 primary isolates evaluated, but exhibited limited cross-neutralization of non-subtype B HIV-1 strains. Taken together, these data demonstrated that the limited neutralization profile of antibodies induced by optimal subtype B V3 motifs likely represents the maximum breadth of neutralization of subtype B HIV-1 primary isolates attainable by anti-V3 peptide antibodies.
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Affiliation(s)
- Barton F Haynes
- Department of Medicine and Human Vaccine Institute, Duke University School of Medicine, Durham, NC 27710, USA.
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5
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Vlad AM, Kettel JC, Alajez NM, Carlos CA, Finn OJ. MUC1 immunobiology: from discovery to clinical applications. Adv Immunol 2004; 82:249-93. [PMID: 14975259 DOI: 10.1016/s0065-2776(04)82006-6] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Anda M Vlad
- Department of Immunology, University of Pittsburgh School of Medicine Pittsburgh, Pennsylvania 15261, USA
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6
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Stanfield RL, Gorny MK, Williams C, Zolla-Pazner S, Wilson IA. Structural Rationale for the Broad Neutralization of HIV-1 by Human Monoclonal Antibody 447-52D. Structure 2004; 12:193-204. [PMID: 14962380 DOI: 10.1016/j.str.2004.01.003] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2003] [Revised: 10/17/2003] [Accepted: 10/18/2003] [Indexed: 11/20/2022]
Abstract
447-52D is a human monoclonal antibody isolated from a heterohybridoma derived from an HIV-1-infected individual. This antibody recognizes the hypervariable gp120 V3 loop, and neutralizes both X4 and R5 primary isolates, making it one of the most effective anti-V3 antibodies characterized to date. The crystal structure of the 447-52D Fab in complex with a 16-mer V3 peptide at 2.5 A resolution reveals that the peptide beta hairpin forms a three-stranded mixed beta sheet with complementarity determining region (CDR) H3, with most of the V3 side chains exposed to solvent. Sequence specificity is conferred through interaction of the type-II turn (residues GPGR) at the apex of the V3 hairpin with the base of CDR H3. This novel mode of peptide-antibody recognition enables the antibody to bind to many different V3 sequences where only the GPxR core epitope is absolutely required.
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Affiliation(s)
- Robyn L Stanfield
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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7
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Hong-Geller E, Möllhoff M, Shiflett PR, Gupta G. Design of Chimeric Receptor Mimics with Different TcRVβ Isoforms. J Biol Chem 2004; 279:5676-84. [PMID: 14604991 DOI: 10.1074/jbc.m309388200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Staphylococcus aureus enterotoxins (S.E.) A-I, and toxic-shock syndrome toxin TSST-1 act as superantigens to cause overstimulation of the host immune system, leading to the onset of various diseases including food poisoning and toxic shock syndrome. SAgs bind as intact proteins to the DRalpha1 domain of the MHC class II receptor and the TcRVbeta domain from the T cell receptor and cause excessive release of cytokines such as IL-2, TNF-alpha, and IFN-gamma, and hyperproliferation of T cells. In addition, different SAgs bind and activate different TcRVbeta isoforms during pathogenesis of human immune cells. These two properties of SAgs prompted us to design several chimeric DRalpha1-linker-TcRVbeta proteins using different TcRVbeta isoforms to create chimeras that would specifically inhibit the pathogenesis of SAgs against which they were designed. In this study, we compare the design, interaction, and inhibitory properties of three different DRalpha1-linker-TcRVbeta chimeras targeted against three different SAgs, SEB, SEC3, and TSST-1. The inhibitory properties of the chimeras were tested by monitoring IL-2 release and T cell proliferation using a primary human cell model. We demonstrate that the three chimeras specifically inhibit the pathogenesis of their target superantigen. We performed molecular modeling to analyze the structural basis of the type specificity exhibited by different chimeras designed against their target SAgs, examine the role of the linker in determining binding and specificity, and suggest site-specific mutations in the chimera to enhance binding affinity. The fact that our strategy works equally well for SEB and TSST-1, two widely different phylogenic variants, suggests that the DRalpha1-linker-TcRVbeta chimeras may be developed as a general therapy against a broad spectrum of superantigens released during Staphylococcal infection.
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MESH Headings
- Amino Acid Sequence
- Antigens/chemistry
- Cell Division
- Cell Line
- Cloning, Molecular
- Enterotoxins/chemistry
- Humans
- Interleukin-2/metabolism
- Kinetics
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Isoforms
- Protein Structure, Tertiary
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Recombinant Fusion Proteins/metabolism
- Sequence Homology, Amino Acid
- Staphylococcus aureus/metabolism
- T-Lymphocytes/metabolism
- Temperature
- Time Factors
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Affiliation(s)
- Elizabeth Hong-Geller
- Los Alamos National Laboratory, Biosciences Division, HRL-1, MS-M888, Los Alamos, New Mexico 87544, USA
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8
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Stanfield RL, Ghiara JB, Ollmann Saphire E, Profy AT, Wilson IA. Recurring conformation of the human immunodeficiency virus type 1 gp120 V3 loop. Virology 2003; 315:159-73. [PMID: 14592768 DOI: 10.1016/s0042-6822(03)00525-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The crystal structure of the human immunodeficiency virus type 1 (HIV-1) neutralizing, murine Fab 83.1 in complex with an HIV-1 gp120 V3 peptide has been determined to 2.57 A resolution. The conformation of the V3 loop peptide in complex with Fab 83.1 is very similar to V3 conformations seen previously with two other neutralizing Fabs, 50.1 and 59.1. The repeated identification of this same V3 conformation in complex with three very different, neutralizing antibodies indicates that it is a highly preferred structure for V3 loops on some strains of the HIV-1 virus.
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Affiliation(s)
- Robyn L Stanfield
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Schuman J, Campbell AP, Koganty RR, Longenecker BM. Probing the conformational and dynamical effects of O-glycosylation within the immunodominant region of a MUC1 peptide tumor antigen. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2003; 61:91-108. [PMID: 12558945 DOI: 10.1034/j.1399-3011.2003.00031.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
MUC1 mucin is a large transmembrane glycoprotein, the extracellular domain of which is formed by a repeating 20 amino acid sequence, GVTSAPDTRPAPGSTAPPAH. In normal breast epithelial cells, the extracellular domain is densely covered with highly branched complex carbohydrate structures. However, in neoplastic breast tissue, the extracellular domain is under-glycosylated, resulting in the exposure of a highly immunogenic core peptide epitope (PDTRP in bold above), as well as in the exposure of normally cryptic core Tn (GalNAc), STn (sialyl alpha2-6 GalNAc) and TF (Gal beta1-3 GalNAc) carbohydrates. Here, we report the results of 1H NMR structural studies, natural abundance 13C NMR relaxation measurements and distance-restrained MD simulations designed to probe the structural and dynamical effects of Tn-glycosylation within the PDTRP core peptide epitope. Two synthetic peptides were studied: a nine-residue MUC1 peptide of the sequence, Thr1-Ser2-Ala3-Pro4-Asp5-Thr6-Arg7-Pro8-Ala9, and a Tn-glycosylated version of this peptide, Thr1-Ser2-Ala3-Pro4-Asp5-Thr6(alphaGalNAc)-Arg7-Pro8-Ala9. The results of these studies show that a type I beta-turn conformation is adopted by residues PDTR within the PDTRP region of the unglycosylated MUC1 sequence. The existence of a similar beta-turn within the PDTRP core peptide epitope of the under-glycosylated cancer-associated MUC1 mucin protein might explain the immunodominance of this region in vivo, as the presence of defined secondary structure within peptide epitope regions has been correlated with increased immunogenicity in other systems. Our results have also shown that Tn glycosylation at the central threonine within the PDTRP core epitope region shifts the conformational equilibrium away from the type I beta-turn conformation and toward a more rigid and extended state. The significance of these results are discussed in relation to the possible roles that peptide epitope secondary structure and glycosylation state may play in MUC1 tumor immunogenicity.
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Affiliation(s)
- J Schuman
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle 98195, USA.
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10
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Gorny MK, Williams C, Volsky B, Revesz K, Cohen S, Polonis VR, Honnen WJ, Kayman SC, Krachmarov C, Pinter A, Zolla-Pazner S. Human monoclonal antibodies specific for conformation-sensitive epitopes of V3 neutralize human immunodeficiency virus type 1 primary isolates from various clades. J Virol 2002; 76:9035-45. [PMID: 12186887 PMCID: PMC136433 DOI: 10.1128/jvi.76.18.9035-9045.2002] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The epitopes of the V3 domain of the human immunodeficiency virus type 1 (HIV-1) gp120 glycoprotein have complex structures consisting of linear and conformational antigenic determinants. Anti-V3 antibodies (Abs) recognize both types of elements, but Abs which preferentially react to the conformational aspect of the epitopes may have more potent neutralizing activity against HIV-1, as recently suggested. To test this hypothesis, human anti-V3 monoclonal Abs (MAbs) were selected using a V3 fusion protein (V3-FP) which retains the conformation of the third variable region. The V3-FP consists of the V3(JR-CSF) sequence inserted into a truncated form of murine leukemia virus gp70. Six human MAbs which recognize epitopes at the crown of the V3 loop were selected with the V3-FP. They were found to react more strongly with molecules displaying conformationally intact V3 than with linear V3 peptides. In a virus capture assay, these MAbs showed cross-clade binding to native, intact virions of clades A, B, C, D, and F. No binding was found to isolates from subtype E. The neutralizing activity of MAbs against primary isolates was determined in three assays: the GHOST cell assay, a phytohemagglutinin-stimulated peripheral blood mononuclear cell assay, and a luciferase assay. While these new MAbs displayed various degrees of activity, the pattern of cross-clade neutralization of clades A, B, and F was most pronounced. The neutralization of clades C and D viruses was weak and sporadic, and neutralization of clade E by these MAbs was not detected. Analysis by linear regression showed a highly significant correlation (P < 0.0001) between the strength of binding of these anti-V3 MAbs to intact virions and the percent neutralization. These studies demonstrate that human MAbs to conformation-sensitive epitopes of V3 display cross-clade reactivity in both binding to native, intact virions and neutralization of primary isolates.
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Affiliation(s)
- Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
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11
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Dumonceaux J, Goujon C, Joliot V, Briand P, Hazan U. Determination of essential amino acids involved in the CD4-independent tropism of the X4 human immunodeficiency virus type 1 m7NDK isolate: role of potential N glycosylations in the C2 and V3 regions of gp120. J Virol 2001; 75:5425-8. [PMID: 11333929 PMCID: PMC114953 DOI: 10.1128/jvi.75.11.5425-5428.2001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Seven mutations in the C2, V3, and C3 regions of gp120 are implicated in the tropism of the first CD4-independent human immunodeficiency virus type 1 isolate, m7NDK. Site-directed mutagenesis revealed that three amino acids are essential to maintain this tropism, one in the C2 region and two in the V3 loop. Two mutations implied N glycosylation modifications.
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Affiliation(s)
- J Dumonceaux
- INSERM Unite 380, Laboratoire de Génétique et Pathologie Expérimentales, Institut Cochin de Génétique Moléculaire, 75014 Paris, France
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12
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Abstract
We synthesized and characterized new chimera peptides by inserting an epitope of the mucin 1 glycoprotein (MUC1) as a 'guest' sequence in the 'host' structure of alpha-conotoxin GI, a 13-residue peptide (ECCNPACGRHYSC) isolated from the venom of Conus geographus. The Pro-Asp-Thr-Arg (PDTR) sequence of MUC1 selected for these studies is highly hydrophilic and adopts a beta-turn conformation. The alpha-conotoxin GI also contains a beta-turn in the 8-12 region, which is stabilized by two disulphide bridges in positions 2-7 and 3-13. Thus, the tetramer sequence of alpha-conotoxin, Arg9-His-Tyr-Ser12, has been replaced by PDTR, comprising the minimal epitope for MUC1 specific monoclonal antibodies (MAbs) HMFG1 (PDTR) and HMFG2 (DTR). Synthesis of the chimera peptide was carried out by Fmoc strategy on (4-(2',4'-dimethoxyphenyl-aminomethyl)phenoxy) (Rink) resin and either 5,5'-dithio-bis-(2-nitrobenzoic acid) (DTNB) or air oxidation was applied for the formation of the first Cys3-Cys13 or Cys2-Cys7 disulphide bridge, respectively. For the second disulphide bridge, three different oxidation procedures (iodine in acetic acid, 10% DMSO/1 M HCl or tallium trifluoroacetate (Tl(tfa)3) in TFA) were utilized. The HPLC purified peptides were characterized by electrospray mass spectrometry (ES-MS) and amino acid analysis. The CD spectra of the bicyclic MUC1-alpha-[Tyr1]-conotoxin chimera peptide showed partially ordered conformation with turn character. In antibody binding studies, the RIA data showed that both the linear and the bicyclic forms of MUC1-alpha-[Tyr1]-conotoxin chimera were recognized by MAb HMFG1 specific for PDTR sequence, while no binding was observed between MAb HMFG2 and various forms of the chimera. MAb HMFG1, using synthetic epitope conjugates or native MUC1 as target antigens, recognizes the PDTR motif more efficiently in the linear than in the bicyclic compound, but no reactivity was found with the monocyclic forms of MUC1-alpha-[Tyr1]-conotoxin chimera, underlining the importance of certain conformers stabilized by double cyclization.
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Affiliation(s)
- E Drakopoulou
- Département d'Ingénierie et d'Etudes des Proteines, CEA, Saclay, Gif-sur-Yvette, France
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13
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Tugarinov V, Anglister J. Solution Structure of an Antibody-Bound HIV-1 IIIBV3 Peptide: A Cis Proline Turn Linking Two β-hairpin Strands. J Biomol Struct Dyn 2000; 17 Suppl 1:57-63. [DOI: 10.1080/07391102.2000.10506604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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14
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Fontenot JD, Tan X, Phillips DM. Structure-based design of peptides that recognize the CD4 binding domain of HIV-1 gp120. AIDS 1998; 12:1413-8. [PMID: 9727561 DOI: 10.1097/00002030-199812000-00002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
DESIGN Envelope protein-specific antiviral peptides, called mucibodies, that can specifically recognize and bind to the surface unit protein gp120 of HIV-1 were designed. The initial mucibody binding target was the V3 loop of HIV-1 gp120. Here, the gp120-CD4 binding domain was chosen as the site of mucibody binding. The CD4 binding domain of gp120 is known to be a conformational epitope and is involved in the earliest events of viral entry into many cells. METHODS The design of the mucibody antivirals was based on previous observations that antibody complementarity determining regions (CDR) are generally similar to the repeating loops or knob structures found in the 20-residue tandem repeat domain of human mucin MUC1. The heavy chain CDR3 from the bacteriophage display antibody b12 was used to construct two mucibodies, b12-CDR1 and b12-26. RESULTS Peptides corresponding to three tandem repeats were shown to bind directly to the CD4 binding domain of HIV-1 gp120 in a solid-phase enzyme-linked immunosorbent assay. These mucibody peptides also disrupted the gp120-CD4 interaction in a solution-phase inhibition assay. Finally, mucibodies neutralized primary and laboratory macrophage-tropic isolates of HIV-1. CONCLUSIONS There is a potential for medical use of these peptides as topical vaginal microbicides in preventing HIV-1 transmission during sexual contact. These results also suggest that multivalent, non-immunogenic binding proteins of virtually any specificity could be constructed for use in therapeutic applications involving infectious diseases and immune system dysfunction.
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Affiliation(s)
- J D Fontenot
- Population Council, Center for Biomedical Research, New York, New York 10021, USA
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15
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FitzGerald DJ, Fryling CM, McKee ML, Vennari JC, Wrin T, Cromwell ME, Daugherty AL, Mrsny RJ. Characterization of V3 loop-Pseudomonas exotoxin chimeras. Candidate vaccines for human immunodeficiency virus-1. J Biol Chem 1998; 273:9951-8. [PMID: 9545339 DOI: 10.1074/jbc.273.16.9951] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To develop a candidate vaccine for human immunodeficiency virus, type 1 (HIV-1), chimeric proteins were constructed by inserting sequences derived from the V3 loop of gp120 into a nontoxic form of Pseudomonas exotoxin (PE). Inserts of 14 or 26 amino acids, constrained by a disulfide bond, were introduced between domains II and III of PE. V3 loop-toxin proteins expressed in Escherichia coli and corresponding to either MN (subtype B) or Thai (subtype E) strains, were recognized by strain-specific monoclonal anti-gp120 antibodies. When loop sequences were introduced into an enzymatically active form of the toxin, there was no loss of toxin-mediated cell killing, suggesting that these sequences were co-transported to the cytosol. Sera from rabbits injected with nontoxic PE-V3 loop chimeras were reactive for strain-specific gp120s in Western blots, immunocapture assays, enzyme-linked immunosorbent assays, and neutralized HIV-1 infectivity. Since toxin vectors were designed to receive oligonucleotide duplexes encoding any V3 loop sequence, this approach should allow for the production of V3 loop-toxin chimeras corresponding to multiple HIV isolates.
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Affiliation(s)
- D J FitzGerald
- Biotherapy Section, Laboratory of Molecular Biology, Division of Basic Science, NCI, National Institutes of Health, Bethesda, Maryland 20892-4255, USA
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16
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Boudet F, Lasarte JJ, Sarobe P, Borras-Cuesta F, Theze J. Fine analysis of immunoreactivity of V3 peptides: antibodies specific for V3 domain of laboratory HIV type 1 strains recognize multiple V3 sequences synthesized from field HIV type 1 isolates. AIDS Res Hum Retroviruses 1996; 12:1671-9. [PMID: 8959242 DOI: 10.1089/aid.1996.12.1671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Production of cross-reactive antibodies recognizing the V3 loop--that is, the principal neutralizing determinant (PND)--of various HIV-1 isolates is an important challenge in the development of passive immunotherapy or vaccinations against AIDS. We have produced two types of antibodies to the V3 domain of HIV-1: (1) antibodies against the HIV-1 MN laboratory strain generated in rabbits and (2) antibodies targeted to the HIV-1 LAI laboratory strain induced in chimpanzees. These antibodies were shown to be specific for HIV-1 subtype B. The cross-reactivity of these antibodies has been evaluated against a large panel of peptides representing different parts of the V3 loop. Seventy-five peptides, referred to as clinical peptides, were synthesized according to HIV-1 sequences recovered from PMBCs of 27 patients followed in three Parisian hospitals. Thirteen V3 peptides derived from 4 HIV-1 laboratory strains (MN, LAI, SF2, and RF) were also included in the study. The results show that both the amino-terminal and central parts of the V3 loop are immunogenic. The rabbit antibodies against the amino-terminal end of the PND proved to be highly cross-reactive against the clinical peptides. The anti-gp160 antibodies induced in one chimpanzee recognized a significant proportion of the panel of V3 clinical sequences. These antibodies cross-reacted mainly with the apex of the V3 loop. These data give some additional indications on the immunogenicity of the V3 loop and further demonstrate that extensive cross-reactivity of anti-V3 antibodies can be obtained on field HIV-1 isolates despite the high variability of the V3 loop amino acid sequence.
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Affiliation(s)
- F Boudet
- Facultad de Medicina, Departamento de Medicina Interna, Universidad de Navarra, Pamplona, Spain
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17
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Fontenot JD, Zacharopoulos VR, Phillips DM. Proline-rich tandem repeats of antibody complementarity-determining regions bind and neutralize human immunodeficiency virus type 1 particles. J Virol 1996; 70:6557-62. [PMID: 8794290 PMCID: PMC190696 DOI: 10.1128/jvi.70.10.6557-6562.1996] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The proline-rich tandem repeat domain of human mucin MUC1 forms an extended structure containing large repeating loops that are crested by a turn. We show that the repeating-loop structure of MUC1 can be replaced by an antibody complementarity-determining region loop of a human immunodeficiency virus type 1 (HIV-1)-specific neutralizing antibody to create a chimeric, multivalent, mucin-like, anti-HIV-1 compound. We used 8 residues of an antibody molecule to replace 8 of 20 residues of the MUC1 tandem-repeat sequence. The antiviral peptide discussed here contains three copies of a 20-residue tandem repeat, (IYYDYEEDPAPGSTAPPAHG)3, for a total of 60 residues. We demonstrate that the mucin-antibody chimera retains the binding specificity of the parent antibody (monoclonal antibody F58), GPGR of the HIV-1 gp120 V3 neutralizing epitope, and the ability to neutralize virus particles. In inhibition enzyme-linked immunosorbent assay, the mucin-antibody chimeric peptide could inhibit 71 to 84% of binding to a V3 loop peptide by monoclonal antibodies known to be specific for GPGR in the V3 loop. The mucin-antibody chimeric peptide could also inhibit monoclonal antibody binding to native gp120 captured from virus particles. In addition, the chimeric peptide neutralized the homologous HIV-IIIB virus in a standard neutralization assay. The methods of antiviral peptide design and construction presented here are general and theoretically limited only by the size of the antibody repertoire. This approach could be used to synthesize peptides for a variety of therapeutic applications.
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Affiliation(s)
- J D Fontenot
- The Population Council, New York, New York 10021, USA
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Huang X, Smith MC, Berzofsky JA, Barchi JJ. Structural comparison of a 15 residue peptide from the V3 loop of HIV-1IIIb and an O-glycosylated analogue. FEBS Lett 1996; 393:280-6. [PMID: 8814305 DOI: 10.1016/0014-5793(96)00912-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
As part of a program to study the effect of glycosylation on the three-dimensional structures of HIV-1IIIB V3 peptide constructs, we have examined the solution structures of a 15 residue peptide (RIQRGPGRAFVTIGK, P18IIIB)- originally mapped as an epitope recognized by CD8+ Dd class I MHC-restricted murine cytotoxic T-lymphocytes (CTL), and an analogue (P18IIIB-g), O-glycosylated with an alpha-galactosamine on Thr-12, using NMR, circular dichroism and molecular modeling methods. Our studies show that the peptides sample mainly random conformations in aqueous solution near 25 degrees C and become more ordered by the addition of trifluoroethanol. Upon decreasing the temperature to 5 degrees C, a reverse turn is formed around the immunodominant tip (G5-R8). Glycosylation on T12 'tightens' the turn slightly as suggested by NOE and CD analysis. In addition, the sugar has a defined conformation with respect to the peptide backbone and influences the local peptide conformation. These data suggest that simple glycosylation may influence the conformational equilibrium of a V3 peptide which contains a domain critical for antibody recognition and virus neutralization. We also show that the ability of cytotoxic T-lymphocytes (CTL) to lyse tumor cells presenting P18IIIB was completely abrogated by threonine glycosylation.
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Affiliation(s)
- X Huang
- Laboratory of Medicinal Chemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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19
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Abstract
The third variable (V3) loop of HIV-1 surface glycoprotein, gp120, has been the target of neutralizing antibodies. However, sequence variation inside the V3 loop diminishes its effectiveness as a potential vaccine against HIV-1. The elusive nature of the V3 loop structure prompted us to carry out a systematic study on different isolates in an attempt to identify a common structural motif in the V3 loop regardless of the amino acid sequence variability. We have previously determined the structural features of two V3 loops: V3 Thailand and V3 MN. In this paper, we present the structure of two other variants: V3 Haiti and V3 RF. Our results show that similar secondary structures are observed in all the four V3 loops: a GPG(R/K/Q) crest in the center of the neutralizing domain, two extended regions flanking the central crest, and a helical region in the C-terminal domain. For the Haitian V3 loop, we also show how the conserved structural features are masked through a conformational switch encoded in the amino acid sequences on the C-terminal side of the GPGK crest.
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Affiliation(s)
- P Catasti
- Theoretical Biology and Biophysics Group, T-10, M/S K710 and the Life Science Division, M/S M881, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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20
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Sherman SA, Gmeiner WH, Kirnarskiy L, Perini F, Ruddon RW. A linear 23-residue peptide reveals a propensity to form an unusual native-like conformation. J Biomol Struct Dyn 1995; 13:441-6. [PMID: 8825723 DOI: 10.1080/07391102.1995.10508853] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To gain insight into the earliest events of protein folding, a 23-residue peptide with a sequence corresponding to the 38-60 fragment of the beta-subunit of human chorionic gonadotropin (hCG beta) was studied by NMR. In aqueous solution the majority of the peptide residues adopted an extended polyproline II (PII) conformation similar to those in mature, fully folded hCG beta. The finding that the isolated protein fragment may acquire native-like structural motifs, even without alpha-helices or beta-structures, extends the possibility of using free peptides as model systems to better understand the protein folding mechanisms. It was shown that the PII-rich structural motif can be determined efficiently by NMR spectroscopy. The observation that in the absence of extensive medium- and long-range interactions the majority of amino acid residues may adopt the PII conformation suggests that the PII-rich structural motifs may play an important role in early events of protein folding.
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Affiliation(s)
- S A Sherman
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805, USA
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