D-Cysteine Ligands Control Metal Geometries within De Novo Designed Three-Stranded Coiled Coils.

ABSTRACT: Although metal ion binding to naturally occurring l-amino acid proteins is well documented, understanding the impact of the opposite chirality (d-)amino acids on the structure and stereochemistry of metals is in its infancy. We examine the effect of a d-configuration cysteine within a designed l-amino acid three-stranded coiled coil in order to enforce a precise coordination number on a metal center. The d chirality does not alter the native fold, but the side-chain re-orientation modifies the sterics of the metal binding pocket. l-Cys side chains within the coiled-coil structure have previously been shown to rotate substantially from their preferred positions in the apo structure to create a binding site for a tetra-coordinate metal ion. However, here we show by X-ray crystallography that

SUBMITTER: Ruckthong L 

PROVIDER: S-EPMC5518473 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature