Regensburg 2013 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

BP: Fachverband Biologische Physik

BP 2: Proteins

BP 2.6: Vortrag

Montag, 11. März 2013, 11:15–11:30, H44

Urea’s effect on protein secondary structures — •Beate Moeser and Dominik Horinek — Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg

Proteins in cells are surrounded by a large variety of chemical compounds (as e. g. metabolites, messenger substances, and osmoregulators). Some of these cosolutes denature proteins and others (over-)stabilize their native fold. This is due to the fact, that they interact differently with different protein secondary structures. The molecular origin thereof, however, is not yet fully understood.

We developed a simulation setup [1] for molecular dynamics simulations, which allows us to quantitatively investigate cosolute effects on various secondary structural elements and provides insight into the molecular forces at play.

Here, we present the influence of the denaturant urea on homopeptides in four distinct conformations: extended strand, 3₁₀-helix, α-helix, and β-sheet. Furthermore, we check, whether the strength of urea’s effect on a given structure is proportional to the solvent accessible surface area of the conformation. This is one of the main assumptions of the group transfer model (TM), which is widely used to predict cosolute effects on proteins. Our quantitative checks allow for a detailed validation and assessment of implementations of the TM and its conclusions concerning the role of the backbone and sidechains in urea denaturation.

[1] Horinek, D., Netz, R.R. 2011. J Phys Chem A 115(23), 6125-6136