Biocatalysts and methods for the synthesis of armodafinil
The present invention relates to non-naturally occurring polypeptides useful for preparing armodafinil, polynucleotides encoding the polypeptides, and methods of using the polypeptides. The non-naturally occurring polypeptides of the present invention are effective in carrying out biocatalytic conversion of the (i) 2-(benzhydrylsulfinyl)acetamide to (−)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide (armodafinil), or (ii) benzhydryl-thioacetic acid to (R)-2-(benzhydrylsulfinyl)acetic acid, which is a pivotal intermediate in the synthesis of armodafinil, in enantiomeric excess.
1. A non-naturally occurring polypeptide having cyclohexanone monooxygenase (CHMO) activity wherein the amino acid sequence of the polypeptide has at least 95% sequence identity to SEQ ID NO:2 and one or more amino acid substitutions at one or more positions in SEQ ID NO: 2 selected from the group consisting of 277, 281, 326, 433, or 435.
2. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide is further capable of converting the acid substrate compound (1b) to compound (2b) (R-enantiomer) or its opposite enantiomer compound (S-enantiomer)
with at least 2-fold improved activity relative to the wild-type polypeptide of SEQ ID NO: 2.
3. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide further comprises one or more amino acid substitutions relative to SEQ ID NO: 2, wherein the polypeptide comprises an alanine, glutamic acid, glycine, isoleucine, lysine, proline, serine, threonine, or valine at a position corresponding to position 246 of SEQ ID NO: 2.
4. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide is further capable of converting the acid substrate of compound (1b) to the R-enantiomer compound (2b)
in at least 50% enantiomeric excess.
5. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide further comprises one or more amino acid differences relative to SEQ ID NO: ID NO: 2, wherein said polypeptide further comprises one or more substitutions corresponding to substitutions in SEQ ID NO: 2 selected from the group consisting of a glycine at position 143, a glycine at position 278, an arginine at position 326, and/or a lysine at position 490.
6. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide further comprises isoleucine at position 277, alanine or glycine at position 278, threonine or tyrosine at position 280, isoleucine at position 281, arginine at position 326, and lysine or glutamine at position 490, wherein the positions correspond to the positions set forth in SEQ ID NO:2.
7. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide is further capable of converting compound (1a) to compound (2a)
in at least 75% enantiomeric excess under suitable reaction conditions.
8. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide is further capable of converting compound (1a) to compound (2a)
with an activity increased at least 2-fold relative to the activity of the polypeptide of SEQ ID NO: 2 under suitable reaction conditions.
9. The non-naturally occurring polypeptide of claim 6 , wherein said polypeptide further comprises a combination of amino acid substitutions relative to SEQ ID NO: 2 selected from the group consisting of:
(a) the amino acid at position 3 is threonine, the amino acid at position 43 is glycine, the amino acid at position 75 is methionine, the amino acid at position 143 is glycine, the amino acid at position 166 is alanine, the amino acid at position 280 is tyrosine, the amino acid at position 395 is arginine, the amino acid at position 412 is leucine, the amino acid at position 426 is serine, the amino acid at position 432 is serine, the amino acid at position 433 is glycine, the amino acid at position 435 is alanine, the amino acid at position 491 is valine, the amino acid at position 503 is alanine, the amino acid at position 504 is isoleucine, the amino acid at position 512 is asparagine, and the amino acid at position 532 is proline;
(b) the amino acid at position 3 is threonine, the amino acid at position 43 is glycine, the amino acid at position 75 is methionine, the amino acid at position 99 is valine, the amino acid at position 143 is glycine, the amino acid at position 161 is aspartic acid, the amino acid at position 166 is alanine, the amino acid at position 174 is isoleucine, the amino acid at position 273 is serine, the amino acid at position 280 is tyrosine, the amino acid at position 324 is lysine, the amino acid at position 395 is arginine, the amino acid at position 412 is leucine, the amino acid at position 426 is serine, the amino acid at position 432 is serine, the amino acid at position 433 is glycine, the amino acid at position 435 is alanine, the amino acid at position 491 is valine, the amino acid at position 503 is alanine, the amino acid at position 504 is isoleucine, the amino acid at position 512 is asparagine, and the amino acid at position 532 is proline; and
(c) the amino acid at position 3 is threonine, the amino acid at position 43 is glycine, the amino acid at position 75 is methionine, the amino acid at position 79 is threonine, the amino acid at position 82 is alanine, the amino acid at position 99 is valine, the amino acid at position 110 is methionine, the amino acid at position 143 is glycine, the amino acid at position 161 is aspartic acid, the amino acid at position 166 is alanine, the amino acid at position 174 is isoleucine, the amino acid at position 208 is threonine, the amino acid at position 273 is serine, the amino acid at position 280 is tyrosine, the amino acid at position 324 is lysine, the amino acid at position 395 is arginine, the amino acid at position 412 is leucine, the amino acid at position 426 is serine, the amino acid at position 432 is serine, the amino acid at position 433 is glycine, the amino acid at position 435 is alanine, the amino acid at position 491 is valine, the amino acid at position 503 is alanine, the amino acid at position 504 is isoleucine, the amino acid at position 505 is lysine, the amino acid at position 512 is asparagine, and the amino acid at position 532 is proline.
10. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide is further capable of converting compound (1b) to compound (2b)
in enantiomeric excess under suitable reaction conditions.
11. The non-naturally occurring polypeptide of claim 6 , wherein said polypeptide is further capable of converting compound (1b) to compound (2b)
in at least 75% enantiomeric excess under suitable reaction conditions.
12. The non-naturally occurring polypeptide of claim 6 , wherein said polypeptide is further capable of converting compound (1b) to compound (2b)
with an activity increased at least 2-fold relative to the activity of the polypeptide of SEQ ID NO: 38 under suitable reaction conditions.
13. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide is further capable of at least 90% or greater conversion of compound (1b) to compound (2b)
in 24 h with a substrate loading of about 50 g/L.
14. The non-naturally occurring polypeptide of claim 1 , wherein said polypeptide further comprises an amino acid difference relative to SEQ ID NO: 2 at one or more positions corresponding to positions in SEQ ID NO: 2 selected from the group consisting of: 32, 40, 42, 54, 62, 74, 123, 135, 163, 171, 176, 182, 192, 227, 246, 288, 290, 313, 314, 322, 329, 336, 348, 364, 373, 382, 430, 472, 478, 489, 538, and 539.
15. The non-naturally occurring polypeptide of claim 14 , wherein said polypeptide comprises one or more substitutions corresponding to substitutions in SEQ ID NO: 2 selected from the group consisting of: the amino acid at position 32 is glutamic acid, the amino acid at position 40 is glycine, the amino acid at position 42 is isoleucine, the amino acid at position 54 is valine, the amino acid at position 62 is valine, the amino acid at position 74 is glutamic acid, the amino acid at position 123 is alanine, the amino acid at position 135 is lysine, the amino acid at position 163 is leucine or tyrosine, the amino acid at position 171 is glycine, the amino acid at position 176 is serine, the amino acid at position 182 is valine, the amino acid at position 192 is valine, the amino acid at position 227 is aspartic acid or glutamic acid, the amino acid at position 264 is tyrosine, the amino acid at position 288 is leucine or valine, the amino acid at position 290 is aspartic acid, the amino acid at position 313 is glutamic acid, the amino acid at position 314 is leucine or threonine, the amino acid at position 322 is glycine or methionine, the amino acid at position 329 is valine, the amino acid at position 336 is serine, the amino acid at position 348 is alanine, the amino acid at position 336 is serine, the amino acid at position 348 is alanine, the amino acid at position 364 is lysine, the amino acid at position 373 is valine, the amino acid at position 382 is arginine, the amino acid at position 430 is arginine, the amino acid at position 472 is isoleucine, the amino acid at position 478 is leucine, the amino acid at position 489 is glycine, the amino acid at position 538 is glutamic acid, and the amino acid at position 539 is glutamic acid.