Metal binding properties of fluorescent analogues of trichogin GA IV: a conformational study by time-resolved spectroscopy and molecular mechanics investigations.
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.
Venanzi
Mariano
M
Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Via della Ricerca Scientifica, Rome, Italy.
Bocchinfuso
Gianfranco
G
Gatto
Emanuela
E
Palleschi
Antonio
A
Stella
Lorenzo
L
Formaggio
Fernando
F
Toniolo
Claudio
C
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
C496789:9-fluorenylmethoxycarbonyl; D005449:Fluorenes; D008051:Lipid Bilayers; D055666:Lipopeptides; C116419:trichogin GA IV; D014867:Water; D005682:Gadolinium; D002118:Calcium