Naslov
Ferrocene chromophore as a potential probe for the assessment of helicity in tripeptides

Autori
Šutalo, Petar ; Nuskol, Marko ; Čakić-Semenčić, Mojca ; Kodrin, Ivan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
5. Simpozij studenata doktorskih studija PMF-a 2021 : knjiga sažetaka / Barišić, Dajana - Zagreb, 2021, 392-392

ISBN
978-953-6076-90-1

Skup
5. Simpozij studenata doktorskih studija PMF-a = 5th Faculty of Science PhD Student Symposium

Mjesto i datum
Zagreb, Hrvatska, 24.04.2021. - 25.04.2021

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
ferrocene chromophore, circular dichroism, monosubstituted ferrocene-based peptidomimetics, molecular mechanics, DFT, QTAIM

Sažetak
Helicity is particularly important for the biological activity of peptides. However, the helicity of conformers in equilibrium for a particular system is often difficult to determine experimentally. Some organic chromophores can act as chiroptical probes for identification of screw- sense preference of peptides by circular dichroism (CD) spectroscopy.[1, 2] Significant number of disubstituted ferrocene peptidomimetics show a positive Cotton effect at 450 nm for the P-helix. Recent research in our group has shown that even small monosubstituted ferrocene-based peptidomimetics synthesized from ferrocenamine show a signal in CD spectra near the absorption maximum of the ferrocene chromophore.[3] To gain a better insight into the key structural properties and geometric parameters associated with a sign of CD spectra of the ferrocene chromophore acting as a probe for determining the helicity of small peptides, Boc-Pro-Pro-Ala-HNFc stereoisomers were studied theoretically. The conformer distribution of each stereoisomer was obtained by a hierarchical approach, searching the conformational potential energy surface employing molecular mechanics and further reoptimized using DFT and implicit solvent model. Quantum theory of atoms in molecules (QTAIM) has confirmed the existence of -turns in the ensemble of the most stable conformers. TD-DFT calculated average CD spectra corroborated the experimental findings. Absorption maximum near 470 nm can be assigned to the d-d transition of ferrocene unit in which directly attached amide group also participates. An origin of the sign change in circular dichroism spectra near the absorption maximum of ferrocene chromophore is strongly related to the sign of dihedral angle describing deviation of the directly attached amide plane from planarity of cyclopentadienyl ring.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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