ORAL PRESENTATION Open Access Can quantum-chemical NMR chemical shifts be used as criterion for force-field development

Fragment-based quantum chemical calculations based on our adjustable density matrix assembler (ADMA) are able to calculate NMR chemical shifts even for proteins and protein-protein complexes [1,2]. The agreement between the calculated and experimental chemical shifts in these calculations is, however, highly dependent on including conformational sampling and explicit solvent molecules. On the one hand, ensembles taken from clas-sical MD simulations are suited for 13C and 1H chemical shift calculations if polar protons are neglected [3]. On the other hand, input structures from a Car–Parrinello MD resulted in landmark improvements over calcula-tions based on classical MD especially for amide pro-tons, which are predicted too high-field shifted based on the latter ensembles [4]. The better results are cause