NMR Structure and Function of Helicoverpa Armigera Sterol Carrier Protein-2, an Important Insecticidal Target from the Cotton Bollworm.
Ma, H., Ma, Y., Liu, X., Dyer, D.H., Xu, P., Liu, K., Lan, Q., Hong, H., Peng, J., Peng, R.(2015) Sci Rep 5: 18186
- PubMed: 26655641
- DOI: https://doi.org/10.1038/srep18186
- Primary Citation of Related Structures:
4UEI - PubMed Abstract:
The cotton bollworm, Helicoverpa armigera, has developed strong resistance to many insecticides. Sterol Carrier Protein-2 (SCP-2) is an important non-specific lipid transfer protein in insects and appears to be a potential new target. In order to elucidate the structure and function of Helicoverpa armigera SCP-2 (HaSCP-2), NMR spectroscopy, docking simulations, mutagenesis and bioassays were performed. HaSCP-2 composed of five α-helices and four stranded β-sheets. The folds of α-helices and β-sheets interacted together to form a hydrophobic cavity with putative entrance and exit openings, which served as a tunnel for accommodating and transporting of lipids. Several sterols and fatty acids could interact with HaSCP-2 via important hydrophobic sites, which could be potential targets for insecticides. Mutagenesis experiments indicated Y51, F53, F89, F110, I117 and Q131 may be the key functional sites. HaSCP-2 showed high cholesterol binding activity and SCP-2 inhibitors (SCPIs) could inhibit the biological activity of HaSCP-2. SCPI-treated larvae at young stage showed a significant decrease of cholesterol uptake in vivo. Our study describes for the first time a NMR structure of SCP-2 in lepidopteran H. armigera and reveals its important function in cholesterol uptake, which facilitates the screening of effective insecticides targeting the insect cholesterol metabolism.
Organizational Affiliation:
School of Life Sciences, Central China Normal University, Wuhan, P.R.China.