Ab initio simulation of chemical shift effects from metal ion binding in Bacitracin A

Ab initio calculations of a chemical shift at the HF/6-31G(d,p)//B3LYP/6-31G(d) level on a model system representing the interaction between Zn++ and the thiazoline ring of Bacitracin A is used for studying the binding mode between the metal ion and the ring system. The simulations show that a reinterpretation of the shift effects seen in the NMR spectra of the zinc–Bacitracin A complex may be needed, because the spectra probably indicate that the Zn++ ion is coordinated by the nitrogen atom of the thiazoline ring rather than the previously assumed sulfur atom. c © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 1–7, 2000