Monitoring Peptide Folding by Time-Resolved Spectroscopies: the Effect of a Single Gly to Aib Susbtitution
We have recently reported on a new fluorescent analogue of trichogin GA IV, a natural peptide showing interesting antimicrobial activity . The primary structure (and acronym) of the peptide investigated is:
Fmoc-Aib-Gly-Leu-Aib-Gly-Gly-Leu-TOAC-Gly-Ile-Leu-OMe (F0T8) where Fmoc is fluorenyl-9-methyloxycarbonyl, Aib is ±-aminoisobutyric acid, TOAC is 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid, and OMe is methoxy.
The double substitution of an energy donor (Fmoc) and an acceptor (TOAC) pair in the trichogin sequence enabled us to make use of time-resolved optical spectroscopies, spanning from the nanosecond to the microsecond time regime, to investigate the conformational propensity and the dynamical features of F0T8. Experimental and computational results indicated that the structural and dynamical properties of F0T8are characterized by a transition from an elongated helical conformation to a more compact structure mimicking a helix-turn-helix...
KeywordsTransient Absorption Peptide Backbone Helical Conformation Aminoisobutyric Acid Microsecond Time Scale
This work was funded by the grant PRIN 2006 (MIUR of Italy).