Ketoreductase polypeptides for the reduction of acetophenones
The present disclosure provides engineered ketoreductase enzymes having improved properties as compared to a naturally occurring wild-type ketoreductase enzyme. Also provided are polynucleotides encoding the engineered ketoreductase enzymes, host cells capable of expressing the engineered ketoreductase enzymes, and methods of using the engineered ketoreductase enzymes to synthesize a variety of chiral compounds.
1. An engineered polynucleotide encoding a recombinant ketoreductase polypeptide capable of stereoselectively reducing acetophenone to (S)-1-phenethanol, wherein said polypeptide comprises an amino acid sequence that is at least 95% identical to the reference sequence of SEQ ID NO: 119, wherein said ketoreductase polypeptide is capable of reducing acetophenone to (S)-1-phenethanol at a rate greater than the rate capable by the ketoreductase polypeptide having the sequence of SEQ ID NO: 6.
2. The engineered polynucleotide of claim 1 , wherein said engineered polynucleotide encodes a recombinant ketoreductase polypeptide capable of stereoselectively reducing the substrate 2′,6′-dichloro-3′-fluoroacetophenone to the product (S)-1-(2,6-dichloro-3-fluorophenyl) ethanol with a percent stereomeric excess of at least 99%.
3. The engineered polynucleotide of claim 1 , wherein said engineered polynucleotide encodes a recombinant ketoreductase polypeptide capable of reducing the substrate 2′,6′-dichloro-3′-fluoroacetophenone to the product (S)-1-(2,6-dichloro-3-fluorophenyl) ethanol at a rate that is at least 450% greater than the rate capable by the ketoreductase polypeptide having the sequence of SEQ ID NO:6.
4. The engineered polynucleotide of claim 1 , wherein said engineered polynucleotide encodes a recombinant ketoreductase polypeptide capable of reducing the substrate 2′,6′-dichloro-3′-fluoroacetophenone to the product (S)-1-(2,6-dichloro-3-fluorophenyl) ethanol at a rate that is at least 1500% greater than the rate capable by the ketoreductase polypeptide having the sequence of SEQ ID NO:6.
5. The engineered polynucleotide of claim 1 , wherein said engineered polynucleotide encodes a recombinant ketoreductase polypeptide comprising a proline at the position corresponding to position 190 of SEQ ID NO:119.
6. An expression vector comprising the engineered polynucleotide of claim 1 .
7. The vector of claim 6 , wherein said polynucleotide is operably linked to regulatory sequences suitable for expression of said polynucleotide in a suitable host cell.
8. The vector of claim 7 , wherein said host cell is a prokaryotic or eukaryotic cell.
9. The vector of claim 8 , wherein said host cell is a prokaryotic cell.
10. The vector of claim 9 , wherein said host cell is E. coli.
11. A host cell comprising the vector of claim 6 .
12. A method for producing at least one recombinant ketoreductase polypeptide comprising culturing the host cell of claim 11 under conditions such that a recombinant ketoreductase polypeptide is produced.
13. The method of claim 12 , further comprising the step of recovering said at least one recombinant ketoreductase polypeptide.