PT  - JOURNAL ARTICLE
AU  - Castle, Linda A.
AU  - Siehl, Daniel L.
AU  - Gorton, Rebecca
AU  - Patten, Phillip A.
AU  - Chen, Yong Hong
AU  - Bertain, Sean
AU  - Cho, Hyeon-Je
AU  - Duck, Nicholas
AU  - Wong, James
AU  - Liu, Donglong
AU  - Lassner, Michael W.
TI  - Discovery and Directed Evolution of a Glyphosate Tolerance Gene
AID  - 10.1126/science.1096770
DP  - 2004 May 21
TA  - Science
PG  - 1151--1154
VI  - 304
IP  - 5674
4099  - http://science.sciencemag.org/content/304/5674/1151.short
4100  - http://science.sciencemag.org/content/304/5674/1151.full
SO  - Science2004 May 21; 304
AB  - The herbicide glyphosate is effectively detoxified by N-acetylation. We screened a collection of microbial isolates and discovered enzymes exhibiting glyphosate N-acetyltransferase (GAT) activity. Kinetic properties of the discovered enzymes were insufficient to confer glyphosate tolerance to transgenic organisms. Eleven iterations of DNA shuffling improved enzyme efficiency by nearly four orders of magnitude from 0.87 mM–1 min–1 to 8320 mM–1 min–1. From the fifth iteration and beyond, GAT enzymes conferred increasing glyphosate tolerance to Escherichia coli, Arabidopsis, tobacco, and maize. Glyphosate acetylation provides an alternative strategy for supporting glyphosate use on crops.