Structural and Evolutionary Studies on Sterol 14-Demethylase P450 (CYP51), the Most Conserved P450 Monooxygenase: II. Evolutionary Analysis of Protein and Gene Structures

Abstract

Phylogenetic analyses based on protein sequence data indicated that sterol 14-demethylase P450 (CYP51) and bacterial CYP51-like protein were joined into a distinctive evolutionary cluster, CYP51 cluster, within the CYP protein superfamily. The most probable branch topology of the CYP51 phylogenetic tree was (bacteria, (plants, (fungi, mammals))), which is comparable to the phylogeny of major kingdoms of living matter, suggesting that CYP51 has been conserved from the era of prokaryotic evolution. This may be strong evidence supporting the prokaryotic origin of P450. Structure of flanking regions and the number and insertion sites of introns are quite different between mammalian and fungal CYP51s. This fact indicates that different mechanisms are operative in evolution of protein sequences and gene structures. CYP51 is the first example violating the well-documented rule that the basic structure of a gene, including intron insertion sites, is well conserved in each P450 family. One CYP51 processed a pseudogene was found in rat genome. Nonsynonymous nucleotide divergence observed between the pseudogene and CYP51 cDNA was less than one-fifth of the synonymous divergence. This unusually low rate of nonsynonymous nucleotide changes in the pseudogene suggests that it may be derived from another CYP51, which might have been active for a significant duration in the past.

Sterol 14α-demethylase cytochrome P450 (CYP51), a P450 in all biological kingdoms

“…Supported by multiple sequence alignment analysis, the idea of the prokaryotic origin of sterol 14α-demethylase might indicate that it is evolutionarily the oldest P450 recognizable today [45,[53][54][55]. Even though an option of horizontal CYP51 gene transfer from plants to currently existing bacteria [31,56] (convolutionary process with loss of function) is not excluded, the CYP51 family remains an intriguing subject to study from two key evolutionary aspects: 1) evolution into different phyla with preserved metabolic role yet sometimes slightly different substrate preferences and 2) possible diversification into other P450 species with altered catalytic function.…”

“…Insertion of sterols into cellular membranes may have paved the way toward the development of eukaryotic organisms [52]. The prokaryotic origin of the sterol biosynthetic pathway implies a common prokaryotic ancestor for all currently existing sterol 14α-demethylases, the only invariant P450 in every known sterol biosynthetic pathway, and in turn provides a very logical explanation for the presence of CYP51 orthologs in all evolutionarily younger biological kingdoms.Supported by multiple sequence alignment analysis, the idea of the prokaryotic origin of sterol 14α-demethylase might indicate that it is evolutionarily the oldest P450 recognizable today [45,[53][54][55]. Even though an option of horizontal CYP51 gene transfer from plants to currently existing bacteria [31,56] (convolutionary process with loss of function) is not excluded, the CYP51 family remains an intriguing subject to study from two key evolutionary aspects: 1) evolution into different phyla with preserved metabolic role yet sometimes slightly different substrate preferences and 2) possible diversification into other P450 species with altered catalytic function.…”

Three-Dimensional Quantitative Structure-Activity Relationship Analysis of Human CYP51 Inhibitors

“…CYP51 is one of the most conserved P450s across phyla (Aoyama et al, 1996;Yoshida et al, 1997), with a 93% amino acid sequence identity between rat and human and 39 to 42% identity between mammalian and fungal enzymes (Aoyama et al, 1996;Yoshida et al, 1997). In humans there are three CYP51 genes, including two pseudogenes and a functional gene on chromosome 7 .…”

“…Substrates for CYP51 from mammals, plants, and fungi are lanosterol, obtusifoliol, and 24-methylene-dihydroxylanosterol, respectively (Lamb et al, 1998). Such substrate specificities can be explained by a limited number of amino acid substitutions in substrate recognition sites 1, 2, and 5 between mammalian and fungal CYP51, and it is likely that these locations are responsible for conferring selectivity for sterol metabolism (Yoshida et al, 1997). Before the sequences of fungal and human CYP51 were known, this enzyme was identified as an antifungal therapeutic target that could be inhibited by many imidazole, triazole (Vanden Bossche et al, 1987Hartman and Sanglard, 1997;Kelly et al, 1997), and nonazole compounds (Aoyama et al, 1983Yoshida and Aoyama, 1985;Gebhardt et al, 1994;Hartman and Sanglard, 1997).…”

A Rice Cytochrome P450OsCYP84AThat May Interact with the UV Tolerance Pathway

“…7) In addition, some catabolites of plant P450s function as endogenous or exogenous signaling compounds in response to environmental stresses. [8][9][10] Members of the CYP72, CYP85, CYP86, CYP74, and CYP97 clans are known to be involved in the catabolism of isoprenoid hormones, the modification of sterols and terpens in the brassinosteroids, the jasmonate and gibberellic acid pathways, [11][12][13][14] the hydroxylation of fatty acids, [15][16][17] the biosynthesis of sterols, 18,19) the synthesis of allene oxide of the intermediates in the biosynthetic pathway of the jasmonate and octadecanoid pathways, 20,21) and the hydroxyration of cartenoids, 22) respectively. Among plant P450s, the CYP71 clan constitutes the largest gene family in the plant genome, and it is widely spread to numerous functions involved in biosynthesis of secondary metabolites, but the functions of most P450s remain unclear.…”