Solution structure of a new hypothalamic neuropeptide, human hypocretin-2/orexin-B.
Lee, J.H., Bang, E., Chae, K.J., Kim, J.Y., Lee, D.W., Lee, W.(1999) Eur J Biochem 266: 831-839
- PubMed: 10583376 
- DOI: https://doi.org/10.1046/j.1432-1327.1999.00911.x
- Primary Citation of Related Structures:  
1CQ0 - PubMed Abstract: 
Orexin-A and orexin-B (also called hypocretin-1 and hypocretin-2, respectively) are novel hypothalamic neuropeptides encoded by a single mRNA transcript; they stimulate food intake. We have determined the three-dimensional solution structure of human hypocretin-2/orexin-B using two-dimensional 1H-NMR data and dynamical simulated annealing calculations. On the basis of NOEs, 3JHNalpha coupling constants and hydrogen-deuterium exchange rates together with chemical shift indices, human hypocretin-2/orexin-B was deduced to consist of two alpha-helices connected with a short linker in both H2O and 30% trifluoroethanol solutions. The helical axis of helix I is oriented about 60-80 degrees relative to helix II. Hybrid distance geometry and simulated-annealing protocols were used to generate an ensemble of 30 structures with no constraint violations greater than 0.03 nm for distances and 3 degrees for angles. In addition, human hypocretin-2/orexin-B shares a similar secondary-structural motif with human neuropeptide Y. This result can form the basis for further study on ligand-receptor recognition of human orexin receptors.
Organizational Affiliation: 
Department of Biochemistry College of Science, Yonsei University, Seoul, Korea.