Abstract:
The classification and characterization of cytochrome P450 monooxygenases in Eurotiomycetes species of fungus have unfolded various structure-function correlates of the enzyme and its variants from the perspective of evolutionary history and drug resistance. The present thesis explored the attributes of azole resistance of Aspergillus strains in terms of point mutations and polymorphisms in CYP51 and CYP51. The azole resistance in Eurotiomycetes was studied Aspergillus fumigatus as the case study. Studies reveal that Aspergillus houses CYP51A and CYP51B and both of them are required for functionality of the CYP51. The CYP51 is chemically 14-alpha demethylase that converts lanosterol to ergosterol. Ergosterol helps in the membrane fluidity and virulence of the fungal isolate. The enzyme is a putative target of azoles, especially the active heme molecule within the active site. The present study was based on in-silico analysis that involved BLAST, FASTA, phylogenetic analysis, and protein modeling to explore the novel single nucleotide polymorphisms and point mutations and its extrapolation to CYP51 structures as enlisted in the PDB database. The study showed that deletion mutations in CYP51 could lead to non-functional 14-alpha demethylase. Moreover, the deletion mutations could also potentiate the over activity of the ABC transporter proteins (efflux pump) because the alignment of the amino acid residues in mutated CYP51 nearly matched that for ABC transporter proteins in the same fungal isolate. It was further contended that mutations in CYP51 promoter could have sensitized the binding of various transcription factors that reduced the expression of 14-alpha demethylase.
