Structures of neuropeptide gamma from goldfish and mammalian neuropeptide gamma, as determined by 1H NMR spectroscopy.
Neuropeptide gamma belongs to tachykinin families which have a common C-terminal amino acid sequence (Phe-X-Leu-Met-NH2) and which induce various biological responses including salivation, hypotension, and contraction of gastrointestinal, respiratory, and urinary smooth muscle. In the present study, we present the solution structures of neuropeptide gamma (NPgamma) from gold fish (G-NPgamma) and mammalian NPgamma (M-NPgamma), as determined by nuclear magnetic resonance (NMR) spectroscopy in 50% trifluoroethanol (TFE)/water (1 : 1, v/v) solution and 200 mm sodium dodecyl sulfate (SDS) micelles. In aqueous TFE solution, G-NPgamma has a alpha-helical conformation in the region of His12-Met21 and a short helix in the N-terminal region, and has a beta-turn from Arg9 to Arg11 in between. In aqueous TFE solution, M-NPgamma also has alpha-helical conformations both in the C-terminal region and the N-terminal region and a beta-turn from His9 to Arg11 in between. In SDS micelle, the structure of G-NPgamma contains a stable alpha-helix from His12 to Met21 and a beta-turn from Arg9 to Arg11, while M-NPgamma has a short helix from Ser16 to Met21. The region from His12 to Met21 corresponds to the amino acid sequence of neurokinin A. Neuropeptide gamma may act as a precursor of neurokinin A and the post-translational processing of this peptide involves the enzymatic attack of the basic beta-turn region from residue 9 to residue 11 in the middle. From our relaxation study, it could be suggested that in fish system G-NPgamma induces the biological actions corresponding to those of substance P in mammalian system. The structures of G-NPgamma and M-NPgamma contain alpha-helical structures at the C-terminus and this helix seems to promote the affinity for NK1 and/or NK2 receptor.
Lee
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K
Department of Chemistry, Konkuk University, Seoul 143-701, Korea.
Lee
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S
Kim
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Park
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D000818:Animals; D002942:Circular Dichroism; D006054:Goldfish; D006168:Guinea Pigs; D008823:Micelles; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D012996:Solutions; D015320:Tachykinins / Q000737:chemistry*
D008823:Micelles; D010446:Peptide Fragments; D012996:Solutions; D015320:Tachykinins; C059905:tachykinin neuropeptide gamma; D012967:Sodium Dodecyl Sulfate