Roles of the variable P450 substrate recognition sites SRS1 and SRS6 in esfenvalerate metabolism by CYP6AE subfamily enzymes in Helicoverpa armigera. (December 2020)

• Record Type: Journal Article
• Authors: Shi, Yu; O'Reilly, Andrias O.; Sun, Shuo; Qu, Qiong; Yang, Yihua; Wu, Yidong
• Is Part Of: Insect biochemistry and molecular biology. Volume 127(2020)
• Publication Date: 2020-12
• Subjects: Helicoverpa armigera -- Cytochrome P450 -- SRS exchange -- Esfenvalerate -- Metabolism -- Molecular modelling; Insect biochemistry -- Periodicals; Insects -- Physiology -- Periodicals; Insects -- Molecular aspects -- Periodicals; Biochemistry -- Periodicals; Insectes -- Biochimie -- Périodiques; Insectes -- Composition -- Périodiques; Insectes -- Physiologie -- Périodiques; Insectes -- Aspect moléculaire -- Périodiques; Biochimie -- Périodiques; Biochemistry; Insect biochemistry; Insects -- Molecular aspects; Insects -- Physiology; Periodicals; 572.8157
• DOI: 10.1016/j.ibmb.2020.103486
• Languages: English
• ISSNs: 0965-1748

Abstract

Abstract: The cotton bollworm P450s of the clustered CYP6AE subfamily share high sequence identities but differ dramatically in their capacity to metabolize xenobiotics, especially esfenvalerate. Among them, CYP6AE17 has the highest sequence identity with CYP6AE18 but shows ~7-fold higher metabolic efficiency. CYP6AE11 is most active towards esfenvalerate but CYP6AE20 is inactive even though the enzymes share 54.8% sequence identity. Sequence analysis revealed the SRS1 (Substrate Recognition Site) and SRS6 between CYP6AE17 and CYP6AE18, and SRS1 between CYP6AE11 and CYP6AE20 are the most variable among all six SRSs. In order to identify the key factors that underlie the observed catalytic difference, we exchanged these SRS sequences between two pairs of P450s and studied the activity of the resulting hybrid mutants or chimeras. In vitro metabolism showed that the CYP6AE17/18 chimeras had 2- and 14-fold decreased activities and the CYP6AE18/17 chimeras had 6- and 10-fold increased activities to esfenvalerate. Meanwhile, after exchanging SRS1 with each other, the CYP6AE11/20 chimera folded incorrectly but the CYP6AE20/11 chimera gained moderate activity to esfenvalerate. Molecular modelling showed that amino acids variants within SRS1 or SRS6 change the shape and chemical environment of the active sites, which may affect the ligand-binding interactions. These results indicate that the protein structure variation resulting from the sequence diversity of SRSs promotes the evolution of insect chemical defense and contributes to the development of insect resistance to pesticides. Graphical abstract: Image 1 Highlights: Many closely-related P450s display significant differences in substrate metabolism. CYP6AEs of Helicoverpa armigera are responsible for xenobiotic detoxification. Two distinctive CYP6AE pairs were studied: CYP6AE11-6AE20 and CYP6AE17-6AE18. Six CYP6AE chimeras were generated by exchanging the SRS1 and SRS6 sections. SRS1 and SRS6 of CYP6AEs were confirmed to determine esfenvalerate metabolism.