AUTHOR=Nuti Francesca , Gellini Cristina , Larregola Maud , Squillantini Lorenzo , Chelli Riccardo , Salvi Pier Remigio , Lequin Olivier , Pietraperzia Giangaetano , Papini Anna Maria TITLE=A Photochromic Azobenzene Peptidomimetic of a β-Turn Model Peptide Structure as a Conformational Switch JOURNAL=Frontiers in Chemistry VOLUME=7 YEAR=2019 URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00180 DOI=10.3389/fchem.2019.00180 ISSN=2296-2646 ABSTRACT=
The insertion of azobenzene moiety in complex molecular protein or peptide systems can lead to molecular switches to be used to determine kinetics of folding/unfolding properties of secondary structures, such as α-helix, β-turn, or β-hairpin. In fact, in azobenzene, absorption of light induces a reversible trans ↔ cis isomerization, which in turns generates a strain or a structure relaxation in the chain that causes peptide folding/unfolding. In particular azobenzene may permit reversible conformational control of hairpin formation. In the present work a synthetic photochromic azobenzene amino acid derivative was incorporated as a turn element to modify the synthetic peptide [Pro7,Asn8,Thr10]CSF114 previously designed to fold as a type I β-turn structure in biomimetic HFA/water solution. In particular, the P-N-H fragment at positions 7–9, involved in a β-hairpin, was replaced by an azobenzene amino acid derivative (synthesized