TY - JOUR
T1 - Biochemical characterisation of Cytochrome P450 oxidoreductase from the cattle tick, Rhipicephalus microplus, highlights potential new acaricide target
AU - Fadahunsi, Adeyinka I.
AU - Kumm, Christopher
AU - Graham, Kirsty
AU - de León, Adalberto A Pérez
AU - Guerrero, Felix
AU - Sparagano, Oliver A E
AU - Finn, Robert
PY - 2023/5/1
Y1 - 2023/5/1
N2 - Management of the cattle tick, Rhipicephalus microplus, presents a challenge because some populations of this cosmopolitan and economically important ectoparasite are resistant to multiple classes of acaricides. Cytochrome P450 oxidoreductase (CPR) is part of the cytochrome P450 (CYP450) monooxygenases that are involved in metabolic resistance by their ability to detoxify acaricides. Inhibiting CPR, the sole redox partner that transfers electrons to CYP450s, could overcome this type of metabolic resistance. This report represents the biochemical characterisation of a CPR from ticks. Recombinant CPR of R. microplus (RmCPR), minus its N-terminal transmembrane domain, was produced in a bacterial expression system and subjected to biochemical analyses. RmCPR displayed a characteristic dual flavin oxidoreductase spectrum. Incubation with nicotinamide adenine dinucleotide phosphate (NADPH) lead to an increase in absorbance between 500 and 600 nm with a corresponding appearance of a peak absorbance at 340-350 nm indicating functional transfer of electrons between NADPH and the bound flavin cofactors. Using the pseudoredox partner, kinetic parameters for both cytochrome c and NADPH binding were calculated as 26.6 ± 11.4 µM and 7.03 ± 1.8 µM, respectively. The turnover, K , for RmCPR for cytochrome c was calculated as 0.08 s which is significantly lower than the CPR homologues of other species. IC (Half maximal Inhibitory Concentration) values obtained for the adenosine analogues 2', 5' ADP, 2'- AMP, NADP and the reductase inhibitor diphenyliodonium were: 140, 82.2, 24.5, and 75.3 µM, respectively. Biochemically, RmCPR resembles CPRs of hematophagous arthropods more so than mammalian CPRs. These findings highlight the potential of RmCPR as a target for the rational design of safer and potent acaricides against R. microplus. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier GmbH.. All rights reserved.]
AB - Management of the cattle tick, Rhipicephalus microplus, presents a challenge because some populations of this cosmopolitan and economically important ectoparasite are resistant to multiple classes of acaricides. Cytochrome P450 oxidoreductase (CPR) is part of the cytochrome P450 (CYP450) monooxygenases that are involved in metabolic resistance by their ability to detoxify acaricides. Inhibiting CPR, the sole redox partner that transfers electrons to CYP450s, could overcome this type of metabolic resistance. This report represents the biochemical characterisation of a CPR from ticks. Recombinant CPR of R. microplus (RmCPR), minus its N-terminal transmembrane domain, was produced in a bacterial expression system and subjected to biochemical analyses. RmCPR displayed a characteristic dual flavin oxidoreductase spectrum. Incubation with nicotinamide adenine dinucleotide phosphate (NADPH) lead to an increase in absorbance between 500 and 600 nm with a corresponding appearance of a peak absorbance at 340-350 nm indicating functional transfer of electrons between NADPH and the bound flavin cofactors. Using the pseudoredox partner, kinetic parameters for both cytochrome c and NADPH binding were calculated as 26.6 ± 11.4 µM and 7.03 ± 1.8 µM, respectively. The turnover, K , for RmCPR for cytochrome c was calculated as 0.08 s which is significantly lower than the CPR homologues of other species. IC (Half maximal Inhibitory Concentration) values obtained for the adenosine analogues 2', 5' ADP, 2'- AMP, NADP and the reductase inhibitor diphenyliodonium were: 140, 82.2, 24.5, and 75.3 µM, respectively. Biochemically, RmCPR resembles CPRs of hematophagous arthropods more so than mammalian CPRs. These findings highlight the potential of RmCPR as a target for the rational design of safer and potent acaricides against R. microplus. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier GmbH.. All rights reserved.]
KW - NADP
KW - P450 oxidoreductase
KW - Rhipicephalus
KW - Mammals
KW - Acaricide target
KW - Tick Infestations - veterinary
KW - Rhipicephalus microplus
KW - Animals
KW - Acaricides - pharmacology
KW - Cattle Diseases - parasitology
KW - Cytochrome P-450 Enzyme System
KW - Enzyme kinetics
KW - Cattle
KW - Cytochromes c
U2 - 10.1016/j.ttbdis.2023.102148
DO - 10.1016/j.ttbdis.2023.102148
M3 - Article
C2 - 36905815
VL - 14
JO - Ticks and Tick-borne Diseases
JF - Ticks and Tick-borne Diseases
SN - 1877-959X
IS - 3
M1 - 102148
ER -