In vitro evolution of a fungal laccase in high concentrations of organic cosolvents.
Fungal laccases are remarkable green catalysts that have a broad substrate specificity and many potential applications in bioremediation, lignocellulose processing, organic synthesis, and more. However, most of these transformations must be carried out at high concentrations of organic cosolvents in which laccases undergo unfolding, thereby losing their activity. We have tailored a thermostable laccase that tolerates high concentrations of cosolvents, the genetic product of five rounds of directed evolution expressed in Saccharomyces cerevisiae. This evolved laccase--R2 variant--was capable of resisting a wide array of cosolvents at concentrations as high as 50% (v/v). Intrinsic laccase features such as the redox potential and the geometry of catalytic copper varied slightly during the course of the molecular evolution. Some mutations at the protein surface stabilized the laccase by allowing additional electrostatic and hydrogen bonding to occur.
Zumárraga
Miren
M
Department of Biocatalysis, Institute of Catalysis, Consejo Superior de Investigaciones Cientificas, Cantoblanco, 28049 Madrid, Spain.
Bulter
Thomas
T
Shleev
Sergey
S
Polaina
Julio
J
Martínez-Arias
Arturo
A
Plou
Francisco J
FJ
Ballesteros
Antonio
A
Alcalde
Miguel
M
D019020:Directed Molecular Evolution; D004795:Enzyme Stability / Q000235:genetics; D005656:Fungal Proteins; D042845:Laccase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009930:Organic Chemicals / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012997:Solvents / Q000494:pharmacology*
D005656:Fungal Proteins; D009930:Organic Chemicals; D012997:Solvents; D042845:Laccase