Using Nonnatural Amino Acids to Control Metal-Coordination Number in Three-Stranded Coiled Coils

摘要

Proteins are remarkably adept at controlling the geometry and the type and number of ligands bound to a metal center.A single protein may contain two or more metal ions in very different coordination environments.For example,5-aminolevulinic acid dehydratase,which is found in mammals and yeast and is involved in the biosynthesis of heme,contains two Zn~(II) ions,one bound in a five-coordinate geometry with oxygen and nitrogen atoms as ligands and the other bound in a pseudo-tetrahedral geometry with three cysteine sulfur atoms and an exogenous water molecule.