Papers In Press, published online ahead of print September 6, 2005
J. Biol. Chem, 10.1074/jbc.M507210200
Submitted on July 5, 2005
Accepted on September 6, 2005
An active enzyme constructed from a nine amino acid alphabet
Kai U. Walter, Katherina Vamvaca, and Donald Hilvert
Laboratory of Organic Chemistry, Swiss Federal Institute of Technology (ETH Zurich), Zurich 8093
Corresponding Author: hilvert{at}org.chem.ethz.ch
Nature employs a set of twenty amino acids to produce a repertoire of protein structures endowed with sophisticated functions. Here, we combined design and selection to create an enzyme composed entirely from a set of only nine amino acids that can rescue auxotrophic cells lacking chorismate mutase. The simplified protein captures key structural features of its natural counterpart but appears to be somewhat less stable and more flexible. The potential of a dramatically reduced amino acid alphabet to produce an active catalyst supports the notion that primordial enzymes may have possessed low amino acid diversity and suggests that combinatorial engineering strategies, like the one used here, may be generally applied to create enzymes with novel structures and functions.