Phylogenetic and Structural Analysis of Polyketide Synthases in Aspergilli

Area of Science:

• Biochemistry
• Molecular Biology
• Mycology

Background:

• Polyketide synthases (PKSs) are crucial enzymes in Aspergillus species, synthesizing diverse polyketide compounds.
• Understanding PKS diversity is vital for applications in medicine, agriculture, and industry.

Purpose of the Study:

• To perform in silico phylogenetic analysis of PKS proteins from six key Aspergillus species.
• To classify Aspergilli PKSs into nonreducing (NR), partially reducing (PR), and highly reducing (HR) types.
• To identify conserved motifs and structural variations in PKS enzymes for novel polyketide discovery.

Main Methods:

• Retrieved full-length PKS and ketosynthase (KS) domain sequences from selected Aspergillus species.
• Conducted independent phylogenetic analyses and classified PKS based on homology with characterized fungal PKS.
• Mapped conserved motifs onto 3D structures of KS domains from NR, PR, and HR PKS types.

Main Results:

• Grouped Aspergilli PKSs into NR, PR, and HR categories, identifying eight distinct clades with unique domain arrangements.
• Observed conserved motif signatures specific to each PKS type.
• Found structural variations in the active sites of modeled NR, PR, and HR enzymes, correlating with product types.

Conclusions:

• The study provides a classification of Aspergillus PKS proteins based on sequence homology, aiding in the exploration of novel polyketides.
• Identified conserved motifs and structural features that can guide the selection of PKS for specific polyketide production.
• The findings facilitate the specific detection of Aspergillus species based on their PKS profiles.