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Evolution of substrate recognition sites (SRSs) in cytochromes P450 from Apiaceae exemplified by the CYP71AJ subfamily.

Dueholm B, Krieger C, Drew D, Olry A, Kamo T, Taboureau O, Weitzel C, Bourgaud F, Hehn A, Simonsen HT - BMC Evol. Biol. (2015)

Bottom Line: Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as 'blooms', providing genetic material for the genesis and evolution of biosynthetic pathways.Homology models underline a significant modification of the accession to the iron atom, which might explain the difference of the substrate specificity between the cytochromes P450 restricted to furanocoumarins as substrates and the orphan CYP71AJ.The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution of cytochrome P450 'blooms' in response to environmental pressures.

View Article: PubMed Central - PubMed

Affiliation: University of Copenhagen, Department of Plant and Environmental Science, Copenhagen Plant Science Centre, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark. bjorn.dueholm@mymail.unisa.edu.au.

ABSTRACT

Background: Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as 'blooms', providing genetic material for the genesis and evolution of biosynthetic pathways. Furanocoumarins are allelochemicals produced by many of the species in Apiaceaous plants belonging to the Apioideae subfamily of Apiaceae and have been described as being involved in the defence reaction against phytophageous insects.

Results: A bloom in the cytochromes P450 CYP71AJ subfamily has been identified, showing at least 2 clades and 6 subclades within the CYP71AJ subfamily. Two of the subclades were functionally assigned to the biosynthesis of furanocoumarins. Six substrate recognition sites (SRS1-6) important for the enzymatic conversion were investigated in the described cytochromes P450 and display significant variability within the CYP71AJ subfamily. Homology models underline a significant modification of the accession to the iron atom, which might explain the difference of the substrate specificity between the cytochromes P450 restricted to furanocoumarins as substrates and the orphan CYP71AJ.

Conclusion: Two subclades functionally assigned to the biosynthesis of furanocoumarins and four other subclades were identified and shown to be part of two distinct clades within the CYP71AJ subfamily. The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution of cytochrome P450 'blooms' in response to environmental pressures.

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Simplified furanocoumarin biosynthesis pathway. Grey dots corresponds to demonstrate or putative cytochrome P450 dependent steps
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Fig1: Simplified furanocoumarin biosynthesis pathway. Grey dots corresponds to demonstrate or putative cytochrome P450 dependent steps

Mentions: Furanocoumarins are molecules often used to illustrate this coevolution. Two kinds of furanocoumarins are described, which differ by the position of a furan group grafted on a coumarin core molecule either at position C6-C7 for linear molecules or C7-C8 for the angular one (Fig. 1). Due to their chemical structure, the linear molecules are highly toxic to a broad spectrum of predators. Although angular molecules are less toxic, the resistance spectrum is expanded when the plants simultaneously produce both linear and angular structures. These kinds of molecules have been reported to exist predominantly in four plant families: Rutaceae, Moraceae, Fabaceae and Apiaceae (for review see [4]). The distribution of linear and angular furanocoumarins differs between each of these four plant families, highlighting a difference in their evolutionary path. In particular, only linear furanocoumarins have been reported in Rutaceae and Moraceae, while both linear and angular furanocoumarins have been described in Fabaceae. It is important to note that no plant has so far been identified that produces only angular molecules, which has led some authors to conclude that linear furanocoumarins appeared earlier during evolution and that the rise of the angular molecules was related to a strengthening of the defensive capacity of plants with respect to the attack by phytopathogenic insects [5]. Apiaceae, the fourth family to produce furanocoumarins, is an interesting case study since they comprise the 3 possible evolutionary stages related to the occurrence of furanocoumarins in higher plants: (i) some species of Apiaceae are unable to synthesize these molecules, (ii) others are able to synthesize only linear furanocoumarins, (iii) and others contain both linear and angular molecules. Within Apiaceae the subfamily Apioideae is the largest of the four subfamilies described in Apiaceae consisting of more than 2900 species and more than 400 genera [6, 7], even though many of these genera are not well resolved [8]. The other subfamilies are Azorelloideae, Mackinlayoideae, and Saniculoideae, and more than 180 species in Apiaceae have not been classified in sub-families but have been classified in tribes only [6, 9–11].Fig. 1


Evolution of substrate recognition sites (SRSs) in cytochromes P450 from Apiaceae exemplified by the CYP71AJ subfamily.

Dueholm B, Krieger C, Drew D, Olry A, Kamo T, Taboureau O, Weitzel C, Bourgaud F, Hehn A, Simonsen HT - BMC Evol. Biol. (2015)

Simplified furanocoumarin biosynthesis pathway. Grey dots corresponds to demonstrate or putative cytochrome P450 dependent steps
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4482195&req=5

Fig1: Simplified furanocoumarin biosynthesis pathway. Grey dots corresponds to demonstrate or putative cytochrome P450 dependent steps
Mentions: Furanocoumarins are molecules often used to illustrate this coevolution. Two kinds of furanocoumarins are described, which differ by the position of a furan group grafted on a coumarin core molecule either at position C6-C7 for linear molecules or C7-C8 for the angular one (Fig. 1). Due to their chemical structure, the linear molecules are highly toxic to a broad spectrum of predators. Although angular molecules are less toxic, the resistance spectrum is expanded when the plants simultaneously produce both linear and angular structures. These kinds of molecules have been reported to exist predominantly in four plant families: Rutaceae, Moraceae, Fabaceae and Apiaceae (for review see [4]). The distribution of linear and angular furanocoumarins differs between each of these four plant families, highlighting a difference in their evolutionary path. In particular, only linear furanocoumarins have been reported in Rutaceae and Moraceae, while both linear and angular furanocoumarins have been described in Fabaceae. It is important to note that no plant has so far been identified that produces only angular molecules, which has led some authors to conclude that linear furanocoumarins appeared earlier during evolution and that the rise of the angular molecules was related to a strengthening of the defensive capacity of plants with respect to the attack by phytopathogenic insects [5]. Apiaceae, the fourth family to produce furanocoumarins, is an interesting case study since they comprise the 3 possible evolutionary stages related to the occurrence of furanocoumarins in higher plants: (i) some species of Apiaceae are unable to synthesize these molecules, (ii) others are able to synthesize only linear furanocoumarins, (iii) and others contain both linear and angular molecules. Within Apiaceae the subfamily Apioideae is the largest of the four subfamilies described in Apiaceae consisting of more than 2900 species and more than 400 genera [6, 7], even though many of these genera are not well resolved [8]. The other subfamilies are Azorelloideae, Mackinlayoideae, and Saniculoideae, and more than 180 species in Apiaceae have not been classified in sub-families but have been classified in tribes only [6, 9–11].Fig. 1

Bottom Line: Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as 'blooms', providing genetic material for the genesis and evolution of biosynthetic pathways.Homology models underline a significant modification of the accession to the iron atom, which might explain the difference of the substrate specificity between the cytochromes P450 restricted to furanocoumarins as substrates and the orphan CYP71AJ.The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution of cytochrome P450 'blooms' in response to environmental pressures.

View Article: PubMed Central - PubMed

Affiliation: University of Copenhagen, Department of Plant and Environmental Science, Copenhagen Plant Science Centre, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark. bjorn.dueholm@mymail.unisa.edu.au.

ABSTRACT

Background: Large proliferations of cytochrome P450 encoding genes resulting from gene duplications can be termed as 'blooms', providing genetic material for the genesis and evolution of biosynthetic pathways. Furanocoumarins are allelochemicals produced by many of the species in Apiaceaous plants belonging to the Apioideae subfamily of Apiaceae and have been described as being involved in the defence reaction against phytophageous insects.

Results: A bloom in the cytochromes P450 CYP71AJ subfamily has been identified, showing at least 2 clades and 6 subclades within the CYP71AJ subfamily. Two of the subclades were functionally assigned to the biosynthesis of furanocoumarins. Six substrate recognition sites (SRS1-6) important for the enzymatic conversion were investigated in the described cytochromes P450 and display significant variability within the CYP71AJ subfamily. Homology models underline a significant modification of the accession to the iron atom, which might explain the difference of the substrate specificity between the cytochromes P450 restricted to furanocoumarins as substrates and the orphan CYP71AJ.

Conclusion: Two subclades functionally assigned to the biosynthesis of furanocoumarins and four other subclades were identified and shown to be part of two distinct clades within the CYP71AJ subfamily. The subclades show significant variability within their substrate recognition sites between the clades, suggesting different biochemical functions and providing insights into the evolution of cytochrome P450 'blooms' in response to environmental pressures.

Show MeSH