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Conformational study of insect adipokinetic hormones using NMR constrained molecular dynamics
M M Nair1, G E Jackson, G Gäde
1Department of Chemistry, University of Cape Town, South Africa.
Journal of Computer-Aided Molecular Design
|April 6, 2001
Summary
Adipokinetic hormones like Mem-CC and Tem-HrTH regulate insect energy metabolism. Structural analysis reveals key differences in their beta-turns, impacting receptor interactions and insect mobility.
Area of Science:
- Insect physiology
- Biochemistry
- Molecular biology
Background:
- Adipokinetic hormones (AKHs) regulate energy metabolism during insect flight.
- Mem-CC, Tem-HrTH, and Del-CC are AKHs isolated from insect corpora cardiaca.
- These hormones are crucial for insect mobility.
Purpose of the Study:
- To determine the secondary structures of Mem-CC, Tem-HrTH, Del-CC, and the [N7]-Mem-CC analogue.
- To investigate the structural basis for receptor binding and activation by AKHs.
Main Methods:
- Nuclear Magnetic Resonance (NMR) restrained molecular mechanics simulations.
- Analysis of peptide structures in dimethyl sulfoxide (DMSO) solution.
Main Results:
- All studied neuropeptides exhibit an extended structure for the first 4 residues.
- A beta-turn structure was identified between residues 4-8 in all peptides.
- In Tem-HrTH and Del-CC, asparagine at position 7 (N7) projects outward from the beta-turn.
- [N7]-Mem-CC shows the N7 sidechain folding inward, hindering receptor interaction.
Conclusions:
- The secondary structure of AKHs is characterized by an extended N-terminus and a C-terminal beta-turn.
- The position of N7 is critical for receptor binding and activation.
- Structural variations in AKHs, particularly at N7, influence their biological activity and receptor interaction.