Journal of Peptide Science

Cover image for Vol. 19 Issue 5

May 2013

Volume 19, Issue 5

Pages 263–332

  1. Research Articles

    1. Top of page
    2. Research Articles
    1. Rapid high-yield N-acylation of aminothiols: N-acetylglutathione and N-acetylhomocysteine and their thiol pKa values (pages 263–267)

      Biao Shen, Cynthia Bazin and Ann M. English

      Version of Record online: 27 MAR 2013 | DOI: 10.1002/psc.2492

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      Rapid, high-yield N-acetylation of aminodisulfides in aqueous medium under mild conditions is accomplished using the activated ester, N-hydroxysulfosuccinimidyl acetate. Heterogeneous reduction of the diN-acetylated aminodisulfides by agarose-bound tris(2-carboxyethyl)phosphine yields the corresponding N-acetylated aminothiols in ~1 h without further purification. The acid dissociation constants of the thiol groups of N-acetylglutathione and N-acetylhomocysteine prepared under these conditions were determined, which expands the set of known thiol pKa values of biological interest.

    2. Synthesis of new vasotocin analogues: effects on renal water and ion excretion in rats (pages 268–276)

      Anna V. Kutina, Anna S. Marina, Ivan I. Eliseev, Mikhail I. Titov and Yuri V. Natochin

      Version of Record online: 27 MAR 2013 | DOI: 10.1002/psc.2495

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      New analogues of antidiuretic hormones (vasotocin and vasopressin) were synthesised by solid-phase technology. Peptides modified at positions 4 and 8 exerted discriminative effects on water reabsorption and excretion of sodium and potassium. Synthesised vasotocin analogues could be good candidates for pharmaceuticals selectively regulating not only water but also sodium and potassium renal transport, which is of clinical importance.

    3. Aromatic interactions with naphthylalanine in a β-hairpin peptide (pages 277–282)

      Daniel Meyer, Caleb Mutschler, Ian Robertson, Alexandra Batt and Chad Tatko

      Version of Record online: 2 MAR 2013 | DOI: 10.1002/psc.2496

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      The stabilization of secondary structures is dramatically influenced by noncovalent interactions. Aromatic interactions are found in all essential biological molecules. Elaboration of this interaction can be achieved with unnatural residues. Naphthylalanine derivatives show their ability to stabilize β-hairpin peptides through edge to face geometries. 1-Naphthylalanine yields a tight interaction geometry while conferring significant stability.

    4. Self-assembly of designed coiled coil peptides studied by small-angle X-ray scattering and analytical ultracentrifugation (pages 283–292)

      Leila Malik, Jesper Nygaard, Niels J. Christensen, Werner W. Streicher, Peter W. Thulstrup, Lise Arleth and Knud J. Jensen

      Version of Record online: 17 MAR 2013 | DOI: 10.1002/psc.2497

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      A systematic study of the self-assembly of a small ensemble of coiled coil sequences using small-angle X-ray scattering (SAXS) and analytical ultracentrifugation (AUC) is presented. This study confirms that even minor sequence changes have an effect on the folding topology that can be observed by a combination of circular dichroism spectroscopy, AUC, and SAXS.

    5. New insight into the binding mode of peptides at urotensin-II receptor by Trp-constrained analogues of P5U and urantide (pages 293–300)

      Alfonso Carotenuto, Luigia Auriemma, Francesco Merlino, Antonio Limatola, Pietro Campiglia, Isabel Gomez-Monterrey, Roberta d'Emmanuele di Villa Bianca, Diego Brancaccio, Paolo Santicioli, Stefania Meini, Carlo Alberto Maggi, Ettore Novellino and Paolo Grieco

      Version of Record online: 25 MAR 2013 | DOI: 10.1002/psc.2498

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      Human U-II (hU-II) is a disulfide bridged peptide hormone. It is described as the most potent vasoconstrictor compound identified to date. We have recently identified both a superagonist and an antagonist of hU-II termed P5U and urantide, respectively. We have synthesized four analogues of P5U and urantide in which Trp7 was replaced by the highly constrained l-Tpi or d-Tpi residue. This replacement led to active analogues, which allowed improving the knowledge on structure–activity relationships.

    6. Humanin binds MPP8: mapping interaction sites of the peptide and protein (pages 301–307)

      Vadim V. Maximov, Alina V. Martynenko, Inga P. Arman and Vyacheslav Z. Tarantul

      Version of Record online: 27 MAR 2013 | DOI: 10.1002/psc.2500

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      The peptide humanin binds the MPP8 protein in vivo. This interaction is mediated by the humanin site from 5 to 12 aa. and by the MPP8 region from 431 to 560 aa.

    7. Perfluoro-tert-butyl-homoserine as a sensitive 19F NMR reporter for peptide–membrane interactions in solution (pages 308–314)

      Benjamin C. Buer, Benjamin J. Levin and E. Neil G. Marsh

      Version of Record online: 19 MAR 2013 | DOI: 10.1002/psc.2501

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      Fluorine NMR provides a powerful tool to investigate dynamic biological processes. We synthesized the novel amino acid pFtBSer that contains nine chemically equivalent fluorines. Incorporation of this amino acid into analogs of the antimicrobial peptide MSI-78 demonstrated that peptide–membrane interactions could be detected by 19F NMR at low micromolar concentrations of peptide.

    8. α-N-Protected dipeptide acids: a simple and efficient synthesis via the easily accessible mixed anhydride method using free amino acids in DMSO and tetrabutylammonium hydroxide (pages 315–324)

      G. Verardo and A. Gorassini

      Version of Record online: 14 MAR 2013 | DOI: 10.1002/psc.2503

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      An easy synthesis of α-N-protected dipeptide acids by the coupling reaction of the mixed anhydride of an α-N-protected amino acid with a DMSO solution of the free amino acid and TBA–OH was developed. The present method was also applied to amino acids bearing unprotected no basic functional groups. The basic lysine was able to engage two molecules of mixed anhydride giving the corresponding isotripeptide. The applicability of this protocol for the synthesis of tri- and tetrapeptides was tested.

    9. Structural and functional characterization of peptides derived from the carboxy-terminal region of a defensin from the tick Ornithodoros savignyi (pages 325–332)

      Lezaan Prinsloo, Alex Naidoo, June Serem, Helena Taute, Yasien Sayed, Megan Bester, Albert Neitz and Anabella Gaspar

      Version of Record online: 31 MAR 2013 | DOI: 10.1002/psc.2505

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      Synthetic peptides derived from the C-terminal of tick defensin isoform 2 (Os-Def2) were evaluated in terms of their antibacterial, antioxidant, and cytotoxic activities. Besides exhibiting potent Gram-positive and Gram-negative bactericidal activities, both Os and Os–C were found at a micromolar concentration to display three times more antioxidant activity than glutathione. Moreover, both peptides showed minimal hemolytic and cytotoxic effects, suggesting that these dual functional peptides may hold potential for a wide range of therapeutic applications.