[1] Univ Minnesota, Dept Chem & Biochem, Minneapolis, MN 55455 USA
[2] Univ Minnesota, Dept Mol Biol & Biophys, Minneapolis, MN 55455 USA
[3] Univ Minnesota, Ctr Met Biocatalysis, Minneapolis, MN 55455 USA
[4] Northwestern Univ, Dept Chem, Evanston, IL 60208 USA
[5] Univ Calif Santa Barbara, Dept Mol Cellular & Dev Biol, Santa Barbara, CA 93106 USA
[6] Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA