Optimization and antiviral analysis of peptide ligands for the HIV-1 packaging signal PSI

  • Julia Dietz1,

    Affiliated with

    • Anette Pustowka1,

      Affiliated with

      • Ajit Kaur2,

        Affiliated with

        • Joachim Koch3,

          Affiliated with

          • Sarah Mensch2,

            Affiliated with

            • Stefan Stein1,

              Affiliated with

              • Manuel Grez1,

                Affiliated with

                • Gilles Divita4,

                  Affiliated with

                  • Yves Mély5,

                    Affiliated with

                    • Harald Schwalbe2 and

                      Affiliated with

                      • Ursula Dietrich1

                        Affiliated with

                        Retrovirology20063(Suppl 1):S58

                        DOI: 10.1186/1742-4690-3-S1-S58

                        Published: 21 December 2006

                        Background

                        We selected peptide ligands for the HIV-1 packaging signal PSI by screening phage displayed peptide libraries. Peptide ligands were optimized by screening spot synthesis peptide membranes. The aim of this study is the functional characterization of these peptide ligands with respect to inhibition of HIV-1 replication.

                        Methods

                        Phage displayed peptide libraries were screened with PSI-RNA structures. The Trp-rich peptide motifs were optimized for specific binding on spot synthesis peptide membranes. The best binding peptide was expressed intracellularly in fusion with RFP or linked to a protein transduction domain (PTD) for intracellular delivery. The effects on virion production were analyzed using pseudotyped lentiviral particles.

                        Results

                        After positive and negative selection rounds, phages binding specifically to PSI-RNA were identified by ELISA. Peptide inserts contained conserved motifs of aromatic amino acids known to be implicated in binding of PSI-RNA by the natural Gag ligand. The filter assay identified HKWPWW as the best binding ligand for PSI-RNA, which is delivered into several cell lines by addition of a PTD. Compared to a control peptide, the HKWPWW peptide inhibited HIV-1 replication as deduced from reduced titers of culture supernatants. As HKWPWW also binds to the TAR-RNA like the natural nucleocapsid PSI-RNA ligand, the effect on Tat-TAR inhibition will also be analyzed. Currently T-cell lines are established which stably express HKWPWW as well as a control peptide, which will be infected with HIV-1 to monitor the ability of HKWPWW to inhibit wild type HIV-1 replication.

                        Conclusion

                        The selection of a peptide ligand for PSI-RNA able to inhibit HIV-1 replication proves the suitability of the phage display technology for the selection of peptides binding to RNA-structures. This enables the indentification of peptides serving as leads to interfere with additional targets in the HIV-1 replication cycle.

                        Declarations

                        Acknowledgements

                        This work is supported by the SFB579 "RNA-ligand interactions" and the EU TRIoH program.

                        Authors’ Affiliations

                        (1)
                        Georg-Speyer-Haus
                        (2)
                        Organic Chemistry, J. W. Goethe University
                        (3)
                        Biochemistry, J. W. Goethe University
                        (4)
                        CRBM-CNRS
                        (5)
                        CNRS, Université Louis Pasteur

                        Copyright

                        © Dietz et al 2006

                        This article is published under license to BioMed Central Ltd.

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