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Metal Binding Properties of Fluorescent Analogues of Trichogin GA IV: A Conformational Study by Time‐Resolved Spectroscopy and Molecular Mechanics Investigations
Author(s) -
Venanzi Mariano,
Bocchinfuso Gianfranco,
Gatto Emanuela,
Palleschi Antonio,
Stella Lorenzo,
Formaggio Fernando,
Toniolo Claudio
Publication year - 2009
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200800617
Subject(s) - circular dichroism , molecular mechanics , chemistry , microsecond , molecular dynamics , spectroscopy , fluorescence spectroscopy , peptide , fluorescence , crystallography , metal , stereochemistry , biophysics , computational chemistry , organic chemistry , biochemistry , physics , quantum mechanics , astronomy , biology
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.