| Title: | Substrate-specificity of cytochrome P450-mediated detoxification as an evolutionary strategy for specialization on furanocoumarin-containing hostplants: CYP6AE89 in parsnip webworms |
| Author(s): | Calla B; Wu WY; Dean CAE; Schuler MA; Berenbaum MR; |
| Address: | "Department of Entomology, University of Illinois at Urbana-Champaign, Champaign, IL, USA. Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA" |
| ISSN/ISBN: | 1365-2583 (Electronic) 0962-1075 (Linking) |
| Abstract: | "The parsnip webworm, Depressaria pastinacella, is restricted to two hostplant genera containing six structurally diverse furanocoumarins. Of these, imperatorin is detoxified by a specialized cytochrome P450, CYP6AB3. A previous whole-larva transcriptome analysis confirmed the presence of nine transcripts that belong to the CYP6AE subfamily. Here, by examining midgut-specific gene expression patterns we determined that CYP6AE89 transcripts were highly expressed and furanocoumarin-inducible. Computer docking and energy-minimization of a CYP6AE89 model with all six furanocoumarins showed that 5-methoxylated bergapten and 8-methoxylated xanthotoxin had the smallest distances from the heme to the proton-donor residue in the catalytic I-helix, and that the 5,8-dimethoxylated isopimpinellin and bergapten had the smallest energy-minimized distance from the heme oxygen to the furan ring double bond. To evaluate this prediction, we expressed the CYP6AE89 protein in an Escherichia coli system, and used it to detect high catalytic activity against the two mono-methoxylated linear furanocoumarins - bergapten and xanthotoxin - and weak activity against isopimpinellin. Thus, CYP6AE89, like CYP6AB3, is probably specialized for detoxifying only a subset of hostplant furanocoumarins. A maximum-likelihood tree built with six representative lepidopterans with manually annotated cytochrome P450s shows that CYP6AE89 may have evolved much faster than the other CYP6AE proteins, possibly indicative of host selection pressure" |
| Keywords: | "Animals *Cytochrome P-450 Enzyme System Furocoumarins/chemistry/*metabolism Gastrointestinal Tract/metabolism Gene Expression Profiling Heracleum/chemistry Inactivation, Metabolic Larva/enzymology/genetics/metabolism Moths/*enzymology/genetics/metabolism;" |
| Notes: | "MedlineCalla, B Wu, W-Y Dean, C A E Schuler, M A Berenbaum, M R eng Research Support, U.S. Gov't, Non-P.H.S. England 2019/08/09 Insect Mol Biol. 2020 Feb; 29(1):112-123. doi: 10.1111/imb.12612. Epub 2019 Aug 23" |
