Determinants of regioselective hydroxylation in the fungal polysaccharide monooxygenases

J Am Chem Soc. 2014 Jan 15;136(2):562-5. doi: 10.1021/ja409384b. Epub 2013 Dec 26.


The ubiquitous fungal polysaccharide monooxygenases (PMOs) (also known as GH61 proteins, LPMOs, and AA9 proteins) are structurally related but have significant variation in sequence. A heterologous expression method in Neurospora crassa was developed as a step toward connecting regioselectivity of the chemistry to PMO phylogeny. Activity assays, as well as sequence and phylogenetic analyses, showed that the majority of fungal PMOs fall into three major groups with distinctive active site surface features. PMO1s and PMO2s hydroxylate glycosidic positions C1 and C4, respectively. PMO3s hydroxylate both C1 and C4. A subgroup of PMO3s (PMO3*) hydroxylate C1. Mutagenesis studies showed that an extra subdomain of about 12 amino acids contribute to C4 oxidation in the PMO3 family.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Carbohydrate Conformation
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism*
  • Hydroxylation
  • Mixed Function Oxygenases / chemistry
  • Mixed Function Oxygenases / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Neurospora crassa / enzymology*
  • Phylogeny
  • Polysaccharides / chemistry
  • Polysaccharides / metabolism*
  • Sequence Alignment
  • Stereoisomerism


  • Fungal Proteins
  • Polysaccharides
  • Mixed Function Oxygenases