Dhad variants and methods of screening
AssigneeButamax Advanced Biofuels LLC
InventorsKristen J. Kelly, Rick W. Ye
Life of this patent
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Abstract
Methods of screening for dihydroxy-acid dehydratase (DHAD) variants that display increased DHAD activity are disclosed, along with DHAD variants identified by these methods. Such enzymes can result in increased production of compounds from DHAD requiring biosynthetic pathways. Also disclosed are isolated nucleic acids encoding the DHAD variants, recombinant host cells comprising the isolated nucleic acid molecules, and methods of producing butanol.
Claims36
An isolated polypeptide or fragment thereof having dihydroxy-acid dehydratase (DHAD) activity, wherein the polypeptide or fragment thereof comprises one or more amino acid substitutions selected from:
- (a) aspartic acid at a position corresponding to position 33 of Streptococcus mutans DHAD;
- (b) glutamic acid at a position corresponding to position 62 of Streptococcus mutans DHAD;
- (c) valine at a position corresponding to position 115 of Streptococcus mutans DHAD;
- (d) glutamic acid at a position corresponding to position 116 of Streptococcus mutans DHAD;
- (e) serine at a position corresponding to position 119 of Streptococcus mutans DHAD;
- (f) arginine at a position corresponding to position 158 of Streptococcus mutans DHAD;
- (g) glutamine at a position corresponding to position 176 of Streptococcus mutans DHAD;
- (h) leucine at a position corresponding to position 179 of Streptococcus mutans DHAD;
- (i) arginine at a position corresponding to position 322 of Streptococcus mutans DHAD;
- (j) serine at a position corresponding to position 425 of Streptococcus mutans DHAD;
- (k) glycine at a position corresponding to position 524 of Streptococcus mutans DHAD;
- (l) valine or leucine at a position corresponding to position 562 of Streptococcus mutans DHAD;
- (m) arginine, cysteine, or glycine at a position corresponding to position 563 of Streptococcus mutans DHAD;
- (n) glutamic acid at a position corresponding to position 564 of Streptococcus mutans DHAD;
- and
- (o) aspartic acid at a position corresponding to position 567 of Streptococcus mutans DHAD.
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An isolated polynucleotide molecule comprising a nucleotide sequence that encodes the polypeptide or fragment thereof of any one of the preceding claims.
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Dependencies are inferred from the claim text.