Conformations of insect neuropeptides and dynamics of retinoid receptor proteins: a biomolecular NMR study

Nair, Margie May

Conformations of insect neuropeptides and dynamics of retinoid receptor proteins: a biomolecular NMR study

Thesis / Dissertation

1997

Publisher

University of Cape Town

Department

Department of Chemistry

Faculty

Faculty of Science

Abstract

Nuclear Magnetic Resonance and molecular dynamics simulations were used to study the conformational states of insect neuropeptides. The DMSO~ solution conformations of three adipokinetic hormone octapeptides of different beetle species and of varying biological activity in the locust bioassay as well as a decapeptide adipokinetic hormone insect neuropeptide were investigated. These peptides were found to exist in multiple conformational states with a few dominant conformers. position 4 onwards. All conformers were found to possess some kind of J3 tum from The backbone dynamics of Retinoid Receptor proteins was studied via the measurement of 1~ NMR relaxation parameters. Studies on the extent of picosecond flexibility of the zinc and cadmium Retinoic Acid Receptor DNA-binding domain indicate that the internal mobility is fairly uniform and limited across the protein backbone. The results indicate that the cadmium form of the protein is relatively less mobile than the zinc form. The dynamics of the backbone amide bonds of Retinoid X Receptor DNA-binding domain and its DNA bound form, has been characterised. NMR relaxation data indicate that internal motion across the uncomplexed protein backbone is uniform except for residues comprising C terminal helix. Slow conformational exchange processes are occurring for residues of the second metal finger domain. The DNA bound form of the protein was found to exhibit reduced conformational mobility relative to the unbound form of the receptor.

Keywords

nuclear magnetic resonance

neuropeptides

Reference:

Collections

PhD / Doctoral

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