In order to analyze the P450 signature domains in the selected fungal P450s, we performed ClustalW analysis using Molecular Evolutionary Genetics Analysis (MEGA 5.2.2) software [47] (link). The advantage of using MEGA-based ClustalW is that this program combines both pairwise alignment and multiple alignment as part of ClustalW.
The ClustalW-aligned P450 sequences were analyzed for amino acid patterns in the P450 signature motifs EXXR and CXG. The amino acid residues in P450 signatures were selected from the ClustalW program from MEGA and computed into tabular form. After sorting to ascending order, manual analyses were performed to check the type of amino acids and their count in P450 signature motifs. The proportions of types of amino acids were calculated and presented in both pie charts and tables.
Some P450s showed variations of the EXXR and CXG motifs. The same phenomenon was also reported in the literature [5] (link), [48] (link), [49] (link). Authors have suggested that these P450s may be misaligned or that the P450s are missing the invariant residues at the EXXR and CXG motif. This is unlike the Streptomyces species P450s that did not contain the conserved EXXR domain but rather EVLW and EQILW [27] (link), [28] (link), which had been proved to be functional. Owing to the lack of functional data with regard to the fungal P450s, which lack the EXXR and CXG motifs signature amino acids; we excluded these P450s from this analysis.
The ClustalW-aligned P450 sequences were analyzed for amino acid patterns in the P450 signature motifs EXXR and CXG. The amino acid residues in P450 signatures were selected from the ClustalW program from MEGA and computed into tabular form. After sorting to ascending order, manual analyses were performed to check the type of amino acids and their count in P450 signature motifs. The proportions of types of amino acids were calculated and presented in both pie charts and tables.
Some P450s showed variations of the EXXR and CXG motifs. The same phenomenon was also reported in the literature [5] (link), [48] (link), [49] (link). Authors have suggested that these P450s may be misaligned or that the P450s are missing the invariant residues at the EXXR and CXG motif. This is unlike the Streptomyces species P450s that did not contain the conserved EXXR domain but rather EVLW and EQILW [27] (link), [28] (link), which had been proved to be functional. Owing to the lack of functional data with regard to the fungal P450s, which lack the EXXR and CXG motifs signature amino acids; we excluded these P450s from this analysis.
Free full text: Click here
