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Structure of neuropeptide Y dimer in solution.
D J Cowley1, J M Hoflack, J T Pelton
1Marion Merrell Dow Research Institute, Strasbourg, France.
European Journal of Biochemistry
|May 1, 1992
Summary
Porcine neuropeptide Y forms a dimer with two curved helical units. This structure, determined by NMR, reveals a hydrophobic core and an unstructured N-terminus, with a dissociation constant of 1.6 microM.
Area of Science:
- Biochemistry
- Structural Biology
- Biophysics
Background:
- Neuropeptide Y (NPY) is a crucial peptide hormone involved in various physiological processes.
- Understanding the structural dynamics of NPY is essential for elucidating its function.
- Previous studies have suggested potential oligomerization of NPY, but its precise structure remained unclear.
Purpose of the Study:
- To determine the three-dimensional structure of porcine neuropeptide Y in solution.
- To investigate the oligomeric state and structural features of porcine neuropeptide Y.
- To characterize the dimerization interface and its impact on NPY structure and function.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy, including Nuclear Overhauser Effect (NOE) experiments.
- Distance geometry calculations, energy minimization, and molecular dynamics simulations.
- Intrinsic fluorescence spectroscopy and fluorescence anisotropy measurements.
Main Results:
- The structure revealed a helical segment (residues 11-36) and identified intermolecular distances indicative of dimer formation.
- A dimeric model with antiparallel packing of two curved helical units was generated, featuring a hydrophobic core.
- The N-terminus (residues 1-9) was found to be unstructured and mobile.
- The dimer dissociation constant was determined to be 1.6 +/- 0.6 microM.
- Tyrosine residues were identified within the hydrophobic interface of the dimer, with their rotation restricted.
Conclusions:
- Porcine neuropeptide Y exists as a dimer in solution, characterized by helical structures and a hydrophobic core.
- The dimeric structure influences the environment of tyrosine residues, impacting NPY's intrinsic fluorescence.
- These findings provide critical insights into the structural basis of neuropeptide Y function and regulation.