title: Novel enzyme activities and functional plasticity revealed by recombining highly homologous enzymes.
abstract: BACKGROUND
  Directed evolution by DNA shuffling has been used to modify physical and catalytic properties of biological systems. We have shuffled two highly homologous triazine hydrolases and conducted an exploration of the substrate specificities of the resulting enzymes to acquire a better understanding of the possible distributions of novel functions in sequence space.
  
  
  RESULTS
  Both parental enzymes and a library of 1600 variant triazine hydrolases were screened against a synthetic library of 15 triazines. The shuffled library contained enzymes with up to 150-fold greater transformation rates than either parent. It also contained enzymes that hydrolyzed five of eight triazines that were not substrates for either starting enzyme.
  
  
  CONCLUSIONS
  Permutation of nine amino acid differences resulted in a set of enzymes with surprisingly diverse patterns of reactions catalyzed. The functional richness of this small area of sequence space may aid our understanding of both natural and artificial evolution.
authors.affiliation: Maxygen, Inc., Redwood City, CA 94063, USA.
authors.forename: S
authors.initials: S
authors.lastname: Raillard
authors.forename: A
authors.initials: A
authors.lastname: Krebber
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: J E
authors.initials: JE
authors.lastname: Ness
authors.forename: E
authors.initials: E
authors.lastname: Bermudez
authors.forename: R
authors.initials: R
authors.lastname: Trinidad
authors.forename: R
authors.initials: R
authors.lastname: Fullem
authors.forename: C
authors.initials: C
authors.lastname: Davis
authors.forename: M
authors.initials: M
authors.lastname: Welch
authors.forename: J
authors.initials: J
authors.lastname: Seffernick
authors.forename: L P
authors.initials: LP
authors.lastname: Wackett
authors.forename: W P
authors.initials: WP
authors.lastname: Stemmer
authors.forename: J
authors.initials: J
authors.lastname: Minshull
mesh_terms: D000619:Aminohydrolases; D019020:Directed Molecular Evolution; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D006867:Hydrolases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity / Q000235:genetics; D014227:Triazines / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011506:Proteins; D014227:Triazines; D006867:Hydrolases; D000619:Aminohydrolases; C424706:melamine deaminase; C100894:atrazine chlorohydrolase