title: Metal binding properties of fluorescent analogues of trichogin GA IV: a conformational study by time-resolved spectroscopy and molecular mechanics investigations.
abstract: The metal ion binding properties of two fluorescent analogues of trichogin GA IV, which is a natural undecapeptide showing significant antimicrobial activity, were studied by circular dichroism, time-resolved optical spectroscopy, and molecular mechanics calculations. Binding of Ca(II) and Gd(III) to the peptides investigated was shown to promote a structural transition from highly helical conformations to folded structures characterized by formation of a loop that embedded the metal ion. Time-resolved spectroscopy revealed that peptide dynamics is also remarkably affected by ion binding: peptide-backbone motions slowed down to the microsecond time scale. Finally, molecular mechanics calculations emphasized the role of the central Gly5-Gly6 motif, which allowed for the twisting of the peptide segment that gave rise to the formation of the binding cavity.
authors.affiliation: Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica, Rome, Italy.
authors.forename: Mariano
authors.initials: M
authors.lastname: Venanzi
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Bocchinfuso
authors.forename: Emanuela
authors.initials: E
authors.lastname: Gatto
authors.forename: Antonio
authors.initials: A
authors.lastname: Palleschi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Stella
authors.forename: Fernando
authors.initials: F
authors.lastname: Formaggio
authors.forename: Claudio
authors.initials: C
authors.lastname: Toniolo
mesh_terms: D000042:Absorption; D000595:Amino Acid Sequence; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002463:Cell Membrane Permeability; D002942:Circular Dichroism; D005449:Fluorenes / Q000378:metabolism; D005453:Fluorescence; D005682:Gadolinium / Q000737:chemistry / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism; D055666:Lipopeptides / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D011485:Protein Binding; D013997:Time Factors; D014867:Water / Q000378:metabolism
chemical_list: C496789:9-fluorenylmethoxycarbonyl; D005449:Fluorenes; D008051:Lipid Bilayers; D055666:Lipopeptides; C116419:trichogin GA IV; D014867:Water; D005682:Gadolinium; D002118:Calcium