Participants On This Publication
Organisms In This Publication
Protein Science, 2004      An Evolutionary Route To Xylanase Process Fitness
Nisha Palackal, YaLi Brennan, Walter N. Callen, Paul Dupree, Gerhard Frey, Florence Goubet, Geoffrey P. Hazlewood, Shaun Healey, Young E. Kang, Keith A. Kretz, Edd Lee, Xuqiu Tan, Geoffery L. Tomlinson, John Verruto, Vicky W.K. Wong, Eric J. Mathur, Jay M. Short, Dan E. Robertson and Brian A. Steer
Protein Science, 2004

Directed evolution technologies were used to selectively improve the stability of an enzyme without compromising its catalytic activity. In particular, this paper describes the tandem use of two evolution strategies to evolve a xylanase rendering it tolerant to temperatures in excess of 90°C. A library of all possible 19 amino acid substitutions at each residue position was generated and screened for activity after a temperature challenge. Nine single amino acid residue changes were identified that enhanced thermostability. All 512 possible combinatorial variants of the nine mutations were then generated and screened for improved thermal tolerance under stringent conditions. The screen yielded eleven variants with substantially improved thermal tolerance. Denaturation temperature transition midpoints were increased from 62°C to as high as 96°C. The use of two evolution strategies in combination enabled the rapid discovery of the enzyme variant with the highest degree of fitness (greater thermal tolerance and activity relative to the wild-type parent).
Keywords: directed evolution, thermal stability, thermophilic, xylanase

NOTE: the article text supplied here is for educational purposes only.
*Don't have Adobe Reader? Get the latest version.

NOTE: Some versions of Adobe Reader have problems with Google Chrome. Either resize the browser to view the paper or enable the Chrome internal PDF viewer by entering chrome://plugins in your address bar and clicking enable for the Chrome PDF Viewer plugin.