Taxonomic Distribution of Cytochrome P450 Monooxygenases (CYPs) among the Budding Yeasts (Sub-Phylum Saccharomycotina).

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doi:10.3390/microorganisms7080247

Abstract

Cytochrome P450 monooxygenases (CYPs) are ubiquitous throughout the tree of life and play diverse roles in metabolism including the synthesis of secondary metabolites as well as the degradation of recalcitrant organic substrates. The genomes of budding yeasts (phylum Ascomycota, sub-phylum Saccharomycotina) typically contain fewer families of CYPs than filamentous fungi. There are currently five CYP families among budding yeasts with known function while at least another six CYP families with unknown function (“orphan CYPs”) have been described. The current study surveyed the genomes of 372 species of budding yeasts for CYP-encoding genes in order to determine the taxonomic distribution of individual CYP families across the sub-phylum as well as to identify novel CYP families. Families CYP51 and CYP61 (represented by the ergosterol biosynthetic genes ERG11 and ERG5, respectively) were essentially ubiquitous among the budding yeasts while families CYP52 (alkane/fatty acid hydroxylases), CYP56 (N-formyl-l-tyrosine oxidase) displayed several instances of gene loss at the genus or family level. Phylogenetic analysis suggested that the three orphan families CYP5217, CYP5223 and CYP5252 diverged from a common ancestor gene following the origin of the budding yeast sub-phylum. The genomic survey also identified eight CYP families that had not previously been reported in budding yeasts.

Highlights

The budding yeasts comprise over 1000 described species of predominantly unicellular fungi that include many species of industrial or medical importance [1]
Any protein sequences that did not satisfy the 40% sequence identity threshold were further queried against the Aspergillus nidulans protein complement within GenBank to identify matches against the Asp. nidulans CYPome reference set [23]
The second phase consisted of TBLATSN searches using the Cytochrome P450 monooxygenases (CYPs) reference proteins against individual budding yeast genomes

Summary

Introduction

The budding yeasts (phylum Ascomycota, sub-phylum Saccharomycotina) comprise over 1000 described species of predominantly unicellular fungi that include many species of industrial or medical importance [1]. The assignment of biological functions to such “orphan genes” [4] remains the primary challenge of budding yeast genomics. CYPs are involved in many metabolic processes including the synthesis of secondary metabolites as well as the degradation of complex organic substrates and xenobiotics. Budding yeast genomes contain relatively few CYP genes as a percentage of the total gene content compared to filamentous ascomycete and basidiomycete fungi [6]. Two possible reasons for this lower proportion of CYP-encoding genes is the limited number of metabolic pathways for secondary metabolite synthesis and complex substrate degradation within the budding yeast sub-phylum

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Conclusion