Metalloprotein and redox protein design are rapidly advancing toward the ch
emical synthesis of novel proteins that have predictable structures and fun
ctions. Current data demonstrate a breadth of successful approaches to meta
llopeptide and metalloprotein design based on de novo, rational and combina
torial strategies. These sophisticated synthetic analogs of natural protein
s constructively test our comprehension of metalloprotein structure/functio
n relationships. Additionally, designed redox proteins provide novel constr
ucts for examining the thermodynamics and kinetics of biological electron t
ransfer.