1
|
Mueller LK, Baumruck AC, Zhdanova H, Tietze AA. Challenges and Perspectives in Chemical Synthesis of Highly Hydrophobic Peptides. Front Bioeng Biotechnol 2020; 8:162. [PMID: 32195241 PMCID: PMC7064641 DOI: 10.3389/fbioe.2020.00162] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/18/2020] [Indexed: 12/31/2022] Open
Abstract
Solid phase peptide synthesis (SPPS) provides the possibility to chemically synthesize peptides and proteins. Applying the method on hydrophilic structures is usually without major drawbacks but faces extreme complications when it comes to "difficult sequences." These includes the vitally important, ubiquitously present and structurally demanding membrane proteins and their functional parts, such as ion channels, G-protein receptors, and other pore-forming structures. Standard synthetic and ligation protocols are not enough for a successful synthesis of these challenging sequences. In this review we highlight, summarize and evaluate the possibilities for synthetic production of "difficult sequences" by SPPS, native chemical ligation (NCL) and follow-up protocols.
Collapse
Affiliation(s)
- Lena K. Mueller
- Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Darmstadt University of Technology, Darmstadt, Germany
| | - Andreas C. Baumruck
- Clemens-Schöpf Institute of Organic Chemistry and Biochemistry, Darmstadt University of Technology, Darmstadt, Germany
| | - Hanna Zhdanova
- Department of Chemistry and Molecular Biology, Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Alesia A. Tietze
- Department of Chemistry and Molecular Biology, Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
2
|
Gates ZP, Dhayalan B, Kent SBH. Obviation of hydrogen fluoride in Boc chemistry solid phase peptide synthesis of peptide-αthioesters. Chem Commun (Camb) 2016; 52:13979-13982. [DOI: 10.1039/c6cc07891e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trifluoromethanesulfonic acid performs comparably to hydrogen fluoride for the on-resin global deprotection of peptides prepared by Boc chemistry solid phase peptide synthesis.
Collapse
|
3
|
Paradís-Bas M, Tulla-Puche J, Albericio F. The road to the synthesis of "difficult peptides". Chem Soc Rev 2015; 45:631-54. [PMID: 26612670 DOI: 10.1039/c5cs00680e] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The last decade has witnessed a renaissance of peptides as drugs. This progress, together with advances in the structural behavior of peptides, has attracted the interest of the pharmaceutical industry in these molecules as potential APIs. In the past, major peptide-based drugs were inspired by sequences extracted from natural structures of low molecular weight. In contrast, nowadays, the peptides being studied by academic and industrial groups comprise more sophisticated sequences. For instance, they consist of long amino acid chains and show a high tendency to form aggregates. Some researchers have claimed that preparing medium-sized proteins is now feasible with chemical ligation techniques, in contrast to medium-sized peptide syntheses. The complexity associated with the synthesis of certain peptides is exemplified by the so-called "difficult peptides", a concept introduced in the 80's. This refers to sequences that show inter- or intra-molecular β-sheet interactions significant enough to form aggregates during peptide synthesis. These structural associations are stabilized and mediated by non-covalent hydrogen bonds that arise on the backbone of the peptide and-depending on the sequence-are favored. The tendency of peptide chains to aggregate is translated into a list of common behavioral features attributed to "difficult peptides" which hinder their synthesis. In this regard, this manuscript summarizes the strategies used to overcome the inherent difficulties associated with the synthesis of known "difficult peptides". Here we evaluate several external factors, as well as methods to incorporate chemical modifications into sequences, in order to describe the strategies that are effective for the synthesis of "difficult peptides". These approaches have been classified and ordered to provide an extensive guide for achieving the synthesis of peptides with the aforementioned features.
Collapse
Affiliation(s)
- Marta Paradís-Bas
- Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, 08028 Barcelona, Spain.
| | | | | |
Collapse
|
4
|
Zeng W, Tan ACL, Horrocks K, Jackson DC. A lipidated form of the extracellular domain of influenza M2 protein as a self-adjuvanting vaccine candidate. Vaccine 2015; 33:3526-32. [PMID: 26049002 DOI: 10.1016/j.vaccine.2015.05.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 05/18/2015] [Accepted: 05/21/2015] [Indexed: 12/15/2022]
Abstract
The highly conserved extracellular domain of Matrix protein 2 (M2e) of influenza A virus has been previously investigated as a potential target for an universal influenza vaccine. In this study we prepared four lipopeptide influenza vaccine candidates in which the TLR2 agonist S-[2,3-bis(palmitoyloxy)propyl] cysteine, (Pam2Cys) was attached to either the N- or C-terminus of the M2e consensus sequence SLLTEVETPIRNEWGCRCNDSSDP and its analogue sequence with the two cysteine residues replaced with serine residues. The results of animal study show that each of these lipopeptides induced strong M2e-specific antibody responses in the absence of extraneous T helper cell epitope(s) which are normally incorporated in the previous studies or addition of extraneous adjuvant and that these antibodies are protective against lethal challenge with influenza virus. Comparison of different routes of inoculation demonstrated that intranasal administration of M2e lipopeptide induced higher titers of IgA and IgG2b antibodies in the bronchoalveolar lavage than did subcutaneous vaccination and was better at mitigating the severity of viral challenge. Finally, we show that anti-M2e antibody specificities absent from the antibody repertoire elicited by a commercially available influenza vaccine and by virus infection can be introduced by immunization with M2e-lipopeptide and boosted by viral challenge. Immunization with this lipidated form of the M2e epitope therefore offers a means of using a widely conserved epitope to generate protective antibodies which are not otherwise induced.
Collapse
Affiliation(s)
- Weiguang Zeng
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, Victoria, Australia.
| | - Amabel C L Tan
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Kylie Horrocks
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, Victoria, Australia
| | - David C Jackson
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, Victoria, Australia
| |
Collapse
|
5
|
Góngora-Benítez M, Tulla-Puche J, Albericio F. Handles for Fmoc solid-phase synthesis of protected peptides. ACS COMBINATORIAL SCIENCE 2013; 15:217-28. [PMID: 23573835 DOI: 10.1021/co300153c] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Protected peptide fragments are valuable building blocks for the assembly of large peptide sequences through fragment condensation approaches, whereas protected peptides are typically synthesized for the preparation of amide-bridge cyclic peptides in solution. Efficient synthesis of both protected peptides and protected peptide fragments by solid-phase peptide synthesis methodology requires handles that attach the growing peptides to the polymeric support and can be cleaved under appropriate conditions, while maintaining intact the side-chain protecting groups. Here, we provide an overview of attachment methods described in the literature for the preparation of protected peptides using Fmoc/tBu chemistry, including the most commonly used acid-labile linkers along with the most recent and sophisticated.
Collapse
Affiliation(s)
- Miriam Góngora-Benítez
- Institute for Research in Biomedicine (IRB Barcelona), 08028-Barcelona, Spain
- CIBER-BBN, Barcelona Science Park, 08028-Barcelona, Spain
| | - Judit Tulla-Puche
- Institute for Research in Biomedicine (IRB Barcelona), 08028-Barcelona, Spain
- CIBER-BBN, Barcelona Science Park, 08028-Barcelona, Spain
| | - Fernando Albericio
- Institute for Research in Biomedicine (IRB Barcelona), 08028-Barcelona, Spain
- CIBER-BBN, Barcelona Science Park, 08028-Barcelona, Spain
- Department of Organic Chemistry, University of Barcelona, 08028-Barcelona, Spain
- School of Chemistry and Physics, University of KwaZulu Natal, 4001-Durban, South Africa
| |
Collapse
|
6
|
Valette NM, Radford SE, Harris SA, Warriner SL. Phosphorylation as a tool to modulate aggregation propensity and to predict fibril architecture. Chembiochem 2012; 13:271-81. [PMID: 22174034 PMCID: PMC3531611 DOI: 10.1002/cbic.201100607] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Indexed: 01/21/2023]
Abstract
Despite the importance of post-translational modifications in controlling the solubility and conformational properties of proteins and peptides, precisely how the aggregation propensity of different peptide sequences is modulated by chemical modification remains unclear. Here we have investigated the effect of phosphorylation on the aggregation propensity of a 13-residue synthetic peptide incorporating one or more phosphate groups at seven different sites at various pH values. Fibril formation was shown to be inhibited when a single phosphate group was introduced at all seven locations in the peptide sequence at pH 7.5, when the phosphate group is fully charged. By contrast, when the same peptides were analysed at pH 1.1, when the phosphate is fully protonated, fibrils from all seven peptide sequences form rapidly. At intermediate pH values (pH 3.6) when the phosphate group is mono-anionic, the aggregation propensity of the peptides was found to be highly dependent on the position of the phosphate group in the peptide sequence. Using this information, combined with molecular dynamics (MD) simulations of the peptide sequence, we provide evidence consistent with the peptide forming amyloid fibrils with a class 7 architecture. The results highlight the potential utility of phosphorylation as a method of reversibly controlling the aggregation kinetics of peptide sequences both during and after synthesis. Moreover, by exploiting the ability of the phosphate group to adopt different charge states as a function of pH, and combining experimental insights with atomistic information calculated from MD simulations as pH is varied, we show how the resulting information can be used to predict fibril structures consistent with both datasets, and use these to rationalise their sensitivity of fibrillation kinetics both to the location of the phosphate group and its charge state.
Collapse
Affiliation(s)
- Nathalie M Valette
- School of Chemistry, University of LeedsLeeds, LS21 3DS (UK)
- Astbury Centre for Structural Molecular Biology, University of LeedsLeeds, LS21 3DS (UK)
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of LeedsLeeds, LS21 3DS (UK)
- Institute for Molecular and Cellular Biology, University of LeedsLeeds, LS21 3DS (UK)
| | - Sarah A Harris
- Astbury Centre for Structural Molecular Biology, University of LeedsLeeds, LS21 3DS (UK)
- School of Physics and Astronomy, University of LeedsLeeds, LS21 3DS (UK)
| | - Stuart L Warriner
- School of Chemistry, University of LeedsLeeds, LS21 3DS (UK)
- Astbury Centre for Structural Molecular Biology, University of LeedsLeeds, LS21 3DS (UK)
| |
Collapse
|
7
|
Affiliation(s)
- Albert Isidro-Llobet
- Institute for Research in Biomedicine, Barcelona Science Park, Baldiri Reixac 10, 08028 Barcelona, Spain
| | | | | |
Collapse
|
8
|
Bacsa B, Horváti K, Bõsze S, Andreae F, Kappe CO. Solid-Phase Synthesis of Difficult Peptide Sequences at Elevated Temperatures: A Critical Comparison of Microwave and Conventional Heating Technologies. J Org Chem 2008; 73:7532-42. [DOI: 10.1021/jo8013897] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Bernadett Bacsa
- Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria, Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary, and piCHEM Forschungs und EntwicklungsgmbH, Kahngasse 20, A-8045 Graz, Austria
| | - Kata Horváti
- Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria, Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary, and piCHEM Forschungs und EntwicklungsgmbH, Kahngasse 20, A-8045 Graz, Austria
| | - Szilvia Bõsze
- Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria, Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary, and piCHEM Forschungs und EntwicklungsgmbH, Kahngasse 20, A-8045 Graz, Austria
| | - Fritz Andreae
- Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria, Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary, and piCHEM Forschungs und EntwicklungsgmbH, Kahngasse 20, A-8045 Graz, Austria
| | - C. Oliver Kappe
- Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria, Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, 1117 Budapest, Hungary, and piCHEM Forschungs und EntwicklungsgmbH, Kahngasse 20, A-8045 Graz, Austria
| |
Collapse
|
9
|
Zahariev S, Guarnaccia C, Pongor CI, Quaroni L, Čemažar M, Pongor S. Synthesis of ‘difficult’ peptides free of aspartimide and related products, using peptoid methodology. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2006.04.074] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
10
|
Yau KYF, Dubuc G, Li S, Hirama T, Mackenzie CR, Jermutus L, Hall JC, Tanha J. Affinity maturation of a VHH by mutational hotspot randomization. J Immunol Methods 2005; 297:213-24. [PMID: 15777944 DOI: 10.1016/j.jim.2004.12.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Revised: 11/26/2004] [Accepted: 12/09/2004] [Indexed: 11/17/2022]
Abstract
V(H)Hs from naive libraries have dissociation constants (K(D)s) in the low micromolar range and thus, for most antibody applications, their intrinsic affinities need to be improved significantly. Non-targeted in vitro affinity maturation approaches based on indiscriminate randomization of complementarity-determining region (CDR) residues or random mutagenesis of conventional antibody variable domains have been shown to improve the affinity of recombinant antibodies by 450- to over 6000-fold. A different, targeted approach based on selective randomization of CDR codons containing AGY/RGYW nucleotide mutational hotspots i.e., "hotspot codons", also promises to be very efficient for improving antibody affinities. Here we employed the latter approach for improving the affinity of PTH22, a parathyroid hormone (PTH)-derived peptide-specific V(H)H that was isolated from a naive llama phage display library. A PTH22 mutant ribosome display library was constructed by randomizing nine CDR2 and CDR3 hotspot codons. The affinity improvement of the lead binder was 30-fold, which seems somewhat low in view of the large number of randomized hotspot codons. Nucleotide sequence analyses of PTH22 and 23 naive V(H)Hs suggested that many AGY/RGYW mutational hotspots are not affinity mutational hotspots but play a role in V(H)H solubility, structure, and deletion/insertion events. Our results indicate that the mutagenesis approach described here is beneficial in terms of yielding moderate increases in affinity while fine-tuning physical properties of an antibody.
Collapse
Affiliation(s)
- Kerrm Y F Yau
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268, USA
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Zahariev S, Guarnaccia C, Zanuttin F, Pintar A, Esposito G, Maravić G, Krust B, Hovanessian AG, Pongor S. Efficient synthesis and comparative studies of the arginine and Nomega,Nomega-dimethylarginine forms of the human nucleolin glycine/arginine rich domain. J Pept Sci 2005; 11:17-28. [PMID: 15635723 DOI: 10.1002/psc.577] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Gly- and Arg-rich C-terminal region of human nucleolin is a 61-residue long domain involved in a number of protein-protein and protein-nucleic acid interactions. This domain contains 10 aDma residues in the form of aDma-GG repeats interspersed with Phe residues. The exact role of Arg dimethylation is not known, partly because of the lack of efficient synthetic methods. This work describes an effective synthetic strategy, generally applicable to long RGG peptides, based on side-chain protected aDma and backbone protected dipeptide Fmoc-Gly-(Dmob)Gly-OH. This strategy allowed us to synthesize both the unmodified (N61Arg) and the dimethylated (N61aDma) peptides with high yield ( approximately 26%) and purity. As detected by NMR spectroscopy, N61Arg does not possess any stable secondary or tertiary structure in solution and N(omega),N(omega)-dimethylation of the guanidino group does not alter the overall conformational propensity of this peptide. While both peptides bind single-stranded nucleic acids with similar affinities (K(d) = 1.5 x 10(-7) M), they exhibit a different behaviour in ssDNA affinity chromatography consistent with the difference in pK(a) values. It has been previously shown that N61Arg inhibits HIV infection at the stage of HIV attachment to cells. This study demonstrates that Arg-dimethylated C-terminal domain lacks any inhibition activity, raising the question of whether nucleolin expressed on the cell-surface is indeed dimethylated.
Collapse
Affiliation(s)
- Sotir Zahariev
- Protein Structure and Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Area Science Park, Padriciano 99, 34012 Trieste, Italy.
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
von Eggelkraut-Gottanka R, Machova Z, Grouzmann E, Beck-Sickinger AG. Semisynthesis and characterization of the first analogues of pro-neuropeptide y. Chembiochem 2003; 4:425-33. [PMID: 12740814 DOI: 10.1002/cbic.200200546] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Enzymatic cleavage of prohormone neuropeptide Y (proNPY) leads to mature neuropeptide Y (NPY), a widely distributed neuropeptide with multiple functions both peripherally and centrally. A single dibasic pair of amino acids, Lys38-Arg39, represents the recognition motif for a class of hormone-processing enzymes known as prohormone convertases (PCs). Two members of this PC family, PC1/3 and PC2, are involved in proNPY cleavage. The aim of this work was to establish an effective method for the generation of full-length 69-amino acid proNPY analogues for further studies of prohormone convertase interaction. We have chosen two ligation sites in order to perform the semisynthesis of proNPY analogues by expressed protein ligation (EPL). By using the intein-mediated purification system (IMPACT) with improved conditions for intein splicing, we were able to isolate proNPY 1-40 and proNPY 1-54 fragments as Cterminal thioesters. Peptides bearing Nterminal cysteine instead of the naturally occurring Ser41 and Thr55 residues, respectively, were generated by solid-phase peptide synthesis. Moreover, labels (carboxyfluorescein and biotin) were inserted into the peptide sequences. The synthesis of the [C41]proNPY 41-69 fragment, which proved to be a difficult peptide sequence, could be achieved by the incorporation of two pseudo-proline derivatives. Western blot analysis revealed that all five proNPY analogues are recognized by monoclonal antibodies directed against NPY as well as against the Cflanking peptide of NPY (CPON).
Collapse
|
13
|
Mathieu MN, Wade JD, Catimel B, Bond CP, Nice EC, Summers RJ, Otvos L, Tregear GW. Synthesis, conformational studies and biological activity of Να-mono-biotinylated rat relaxin*. ACTA ACUST UNITED AC 2002; 57:374-82. [PMID: 11350597 DOI: 10.1034/j.1399-3011.2001.00853.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Biotin-avidin immobilization can be a useful tool in structure-function studies of hormone receptors. A crucial step is the preparation of a specifically biotinylated hormone that is able to bind to its receptor while leaving the biotin group free for interaction with avidin. The receptor for relaxin, an ovarian peptidic hormone produced during pregnancy, has not yet been isolated. We therefore undertook to prepare a specifically monobiotinylated rat relaxin for use in ligand-searching strategies. Rat relaxin is a convenient analogue because reliable bioassays exist, thus allowing assessment of the effect of N-biotinylation on bioactivity. To help improve the yield of the two-chain, three-disulfide bond rat relaxin, 2-hydroxy-4-methoxybenzyl (Hmb) backbone protection was used during the solid-phase assembly of the B-chain to help prevent any possible chain aggregation. As a final step, while the protected peptide was still on the resin, the biotin label was introduced at the N-terminus of the B-chain using standard coupling protocols. The chain combination with the A-chain was accomplished in reasonable yield. Secondary structural measurements demonstrated that the biotin caused the starting B-chain to adopt a more ordered conformation. The labelled synthetic relaxin exhibited similar circular dichroism spectra to native and synthetic single B-chain peptides. In addition, the biotinylated relaxin showed no significant difference in its chronotropic activity in the rat isolated heart assay compared with the native peptide. Biosensor studies showed that antibody recognition was retained upon attachment of the synthetic relaxin to the streptavidin-derivatized surface.
Collapse
Affiliation(s)
- M N Mathieu
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Australia.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
González-Muñiz R, Gerona-Navarro G, Angeles Bonache M, Reyero N, Teresa García-López M. Amino Acid-derived 4-Alkyl-4-carboxy-2-azetidinones. New Insights into b-Lactam Ring Formation and N-Deprotection. HETEROCYCLES 2002. [DOI: 10.3987/com-01-9400] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
15
|
Zhang PF, Bouma P, Park EJ, Margolick JB, Robinson JE, Zolla-Pazner S, Flora MN, Quinnan GV. A variable region 3 (V3) mutation determines a global neutralization phenotype and CD4-independent infectivity of a human immunodeficiency virus type 1 envelope associated with a broadly cross-reactive, primary virus-neutralizing antibody response. J Virol 2002; 76:644-55. [PMID: 11752155 PMCID: PMC136808 DOI: 10.1128/jvi.76.2.644-655.2002] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human serum human immunodeficiency virus type 1 (HIV-1)-neutralizing serum 2 (HNS2) neutralizes many primary isolates of different clades of HIV-1, and virus expressing envelope from the same donor, clone R2, is neutralized cross-reactively by HIV-immune human sera. The basis for this cross-reactivity was investigated. It was found that a rare mutation in the proximal limb of variable region 3 (V3), 313-4 PM, caused virus pseudotyped with the R2 envelope to be highly sensitive to neutralization by monoclonal antibodies (MAbs) directed against conformation-sensitive epitopes at the tip of the V3 loop, such as 19b, and moderately sensitive to MAbs against CD4 binding site (CD4bs) and CD4-induced (CD4i) epitopes, soluble CD4 (sCD4), and HNS2. In addition, introduction of this sequence by mutagenesis caused enhanced sensitivity to neutralization by 19b, anti-CD4i MAb, and HNS2 in three other primary HIV-1 envelopes and by anti-CD4bs MAb and sCD4 in one of the three. The 313-4 PM sequence also conferred increased infectivity for CD4(+) CCR5(+) cells and the ability to infect CCR5(+) cells upon all of these four and two of these four HIV-1 envelopes, respectively. Neutralization of R2 by HNS2 was substantially inhibited by the cyclized R2 V3 35-mer synthetic peptide. Similarly, the peptide also had some lesser efficacy in blocking neutralization of R2 by other sera or of neutralization of other primary viruses by HNS2. Together, these results indicate that the unusual V3 mutation in the R2 clone accounts for its uncommon neutralization sensitivity phenotype and its capacity to mediate CD4-independent infection, both of which could relate to immunogenicity and the neutralizing activity of HNS2. This is also the first primary HIV-1 isolate envelope glycoprotein found to be competent for CD4-independent infection.
Collapse
Affiliation(s)
- Peng Fei Zhang
- Department of Preventive Medicine and Biometrics, Biomedical Instrumentation Center, Uniformed Services University of the Health Sciences, Bethesda 20814, USA
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Sampson WR, Patsiouras H, Ede NJ. The synthesis of 'difficult' peptides using 2-hydroxy-4-methoxybenzyl or pseudoproline amino acid building blocks: a comparative study. J Pept Sci 1999; 5:403-9. [PMID: 10526883 DOI: 10.1002/(sici)1099-1387(199909)5:9<403::aid-psc213>3.0.co;2-s] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A comparative study has been undertaken between Hmb-protected amino acid and pseudoproline building block analogues for use in the solid phase synthesis of 'difficult' peptides. Both of these derivatives act by blocking inter- and intramolecular hydrogen bonding, which has been shown to be a major cause of poor synthesis/quality/efficiency. While the two were shown to result in substantial improvements in the purity of crude peptides, pseudoproline incorporation was found to be superior to Hmb backbone protection. This was due to slow and incomplete coupling of the amino acid immediately following the Hmb amino acid.
Collapse
Affiliation(s)
- W R Sampson
- Chiron Technologies Pty. Ltd., Clayton, Victoria, Australia
| | | | | |
Collapse
|
17
|
|
18
|
Clippingdale AB, Macris M, Wade JD, Barrow CJ. Synthesis and secondary structural studies of penta(acetyl-Hmb)A beta(1-40). THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1999; 53:665-72. [PMID: 10408341 DOI: 10.1034/j.1399-3011.1999.00065.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The Fmoc solid phase synthesis of A beta(1-40), a strongly aggregating peptide found in Alzheimer's disease brain, was performed using 2-hydroxy-4-methoxybenzyl (Hmb) backbone amide protection. Hmb-Gly residues were incorporated using N(alpha)-Fmoc-Hmb-Gly-OH rather than N,O-bisFmoc-Hmb-Gly-OPfp. Amino acid acylation of the sterically hindered Hmb-amino acids was monitored using 'semi-on-line' MALDI-TOF-MS in a novel application of this technique which significantly simplified the successful incorporation of these residues. Standard coupling conditions in N,N-dimethylformamide (DMF) were used throughout the synthesis. Comparative structural studies of acetyl-Hmb-protected and native A beta(1-40) were performed to investigate the structural basis of Hmb-mediated disaggregation. The incorporation of backbone amide protection was observed by circular dichroism spectroscopy and gel electrophoresis to strongly affect the solution structure of A beta(1-40). Despite the reported structure-breaking activity of Hmb groups, penta(acetyl-Hmb)A beta(1-40) was found to adopt both alpha-helix and intermolecular beta-sheet conformations. In 100% TFE a mixed alpha-helix/random coil structure was formed by the protected peptide indicating reduced alpha-helical propensity relative to A beta(1-40). The protected peptide formed beta-sheet structures in aqueous buffer. Gel electrophoresis indicated that, unlike native A beta(1-40), penta(acetyl-Hmb)A beta(1-40) did not form large aggregate species.
Collapse
Affiliation(s)
- A B Clippingdale
- School of Chemistry and Howard Florey Institute of Experimental Physiology and Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | | | | | | |
Collapse
|
19
|
Due Larsen B, Holm A. Sequence-assisted peptide synthesis (SAPS). THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1998; 52:470-6. [PMID: 9924991 DOI: 10.1111/j.1399-3011.1998.tb01251.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In solid-phase peptide synthesis (SPPS) the growing peptide chain may undergo chain aggregation which can cause serious synthetic problems. A number of investigations concerning this problem have been reported in the chemical literature. During a study of such "difficult sequences" using the Fmoc-protection strategy, we have observed that peptide-chain aggregation may be significantly reduced when certain amino acid sequences are incorporated C-terminally (1). Thus, synthesis of the difficult poly-alanine, (Ala)n, sequence (n < or = 20) has been investigated with (Lys(Boc))m (m < or = 6) and (Glu(tBu))m (m > or = 6) as pre-sequences. With m > or = 3, peptides are obtained as single, homogeneous products while a complex mixture of deletion peptides and corresponding Fmoc-protected peptides is formed (n > or = 6) without the pre-sequence. A mixed pre-sequence, (Lys(Boc)Glu(tBu))3, has a similar favorable effect on the synthetic results, but the positive effect seems confined to a rather narrow framework of amino acids and side-chain protecting groups in the pre-sequence as discussed in the article. Among other reputedly difficult sequences the synthesis of H-(Thr-Val)5-OH, H-Val-Asn-Val-Asn-Val-Gln-Val-Gln-Val-Asp-OH, the Acyl Carrier Protein (65-74) and the human insulin B-chain has been investigated. In all cases introduction of a pre-sequence gives rise to satisfactory synthetic results. In the latter case, the lysine pre-sequence may be cleaved enzymatically to give the desB30 insulin B-chain. NIR-FT Raman studies of the synthesis of the poly-alanine, (Ala)n, sequences have shown that the pre-sequence (Lys(Boc))6 shifts the conformation of the growing peptide chain from a beta-structure (n > or = 6) to a random coil conformation (1c). This result is in agreement with the general observation that SPPS proceeds optimally under random coil conditions.
Collapse
Affiliation(s)
- B Due Larsen
- Research Center for Medical Biotechnology, Chemistry Department, The Royal Veterinary and Agricultural University, Frederiksberg C, Denmark
| | | |
Collapse
|