Elucidation of the Conformation of Polyglycine Organo-Polyoxotungstates: Evidence for Zipper Folding

The conformation of a family of α1 and α2 polyglycine- containing organo-polyoxometalates was determined via a mixed experimental/molecular dynamics approach. The flexible peptide arm folds around the metal oxide surface in a rigid arrangement in low to average polarity solvents. The topology of the hybrid is the main factor that determines which oxos from the metal-oxide surface accept an H-bond from the closest amino-acid. The rest of the peptide follows in a zipper mechanism that establishes a H-bond network which locks the system. The covalent constraint leads to a new type of H-bond where two consecutive amino-acids clamp down terminal oxo ligands.