Conformational analogy between substance P and physalaemin.
The three-dimensional structure of physalaemin, pGlu-Ala-Asp-Pro-Asn-Lys-Phe-Tyr-Gly-Leu-Met-NH2, has been studied by one- and two-dimensional 500 MHz NMR spectroscopies in two solvents: methanol and dimethyl sulfoxide. As previously observed for substance P in methanol, the core of physalaemin 4----8 is folded into an helical conformation. This structure is stabilized by the presence of a salt bridge between Asp-3 and Lys-6 in both solvents. The only differences observed reside in the N-terminal sequences; the N-terminal tripeptide of substance is flexible whereas that of physalaemin is in an extended conformation.
D000596:Amino Acids / Q000032:analysis; D004121:Dimethyl Sulfoxide; D007705:Kinins; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol; D008958:Models, Molecular; D010803:Physalaemin; D011487:Protein Conformation; D011522:Protons; D012997:Solvents; D013373:Substance P
D000596:Amino Acids; D007705:Kinins; D011522:Protons; D012997:Solvents; D010803:Physalaemin; D013373:Substance P; D000432:Methanol; D004121:Dimethyl Sulfoxide