title: Structural determinants of unexpected agonist activity in a retro-peptide analogue of the SDF-1alpha N-terminus.
abstract: We have synthesised two retro-peptide analogues of the stromal cell derived growth factor 1 (SDF-1alpha) segment known to be critical for CXCR4 receptor binding, corresponding to the sequences HSEFFRCPCRFFESH and HSEFFRGGGRFFESH. We have assayed the ability of these peptides to activate extracellular signal-regulated kinase 1/2 phosphorylation in cells over expressing the SDF-1alpha receptor, finding that the first variant was able to serve as an agonist of CXCR4, whereas the second one was inactive. Finally, by comparing representative solution structures of the two peptides, we have found that the biological response of HSEFFRCPCRFFESH may be ascribed to a beta-beta-type turn motif centred on Phe(4)-Phe(5).
authors.affiliation: Dipartimento delle Scienze Biologiche, CIRPeB, Università Federico II di Napoli, CNR, Italy. palladin@chemistry.unina.it
authors.forename: Pasquale
authors.initials: P
authors.lastname: Palladino
authors.forename: Barbara
authors.initials: B
authors.lastname: Tizzano
authors.forename: Carlo
authors.initials: C
authors.lastname: Pedone
authors.forename: Raffaele
authors.initials: R
authors.lastname: Ragone
authors.forename: Filomena
authors.initials: F
authors.lastname: Rossi
authors.forename: Gabriella
authors.initials: G
authors.lastname: Saviano
authors.forename: Teodorico
authors.initials: T
authors.lastname: Tancredi
authors.forename: Ettore
authors.initials: E
authors.lastname: Benedetti
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000737:chemistry*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011487:Protein Conformation; D019718:Receptors, CXCR4 / Q000819:agonists*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship
chemical_list: D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D010446:Peptide Fragments; D019718:Receptors, CXCR4