Properties of "Stable" Mosquito Cytochrome P450 Enzymes

The use of insecticides is widespread in the control of debilitating mosquito-borne diseases. P450 enzymes (CYPs) play essential roles in mosquito physiological function but also in the enzymatic detoxification of xenobiotics. Broadly speaking, CYPs can be classified as "stable", meaning those that have no or very few paralogs, and "labile", constituting gene families with many paralogous members. The evolutionary dichotomy between "stable" and "labile" P450 genes is fuzzy and there is not a clear phylogenetic demarcation between P450s involved in detoxification and P450s involved in essential metabolic processes. In this study, bioinformatic methods were used to explore differences in the sequences of "stable" and "labile" P450s that may facilitate their functional classification. Genomic and sequence data of Anopheles gambiae (Agam), Aedes aegypti (Aaeg), and Culex quinquefasciatus (Cqui) CYPs were obtained from public databases. The results of this study show that "stable" CYPs are encoded by longer genes, have longer introns and more exons, and contain a higher proportion of hydrophobic amino acids than "labile" CYPs. Compared to "labile" CYPs, a significantly higher proportion of "stable" CYPs are associated with biosynthetic and developmental processes.