Solution Conformation Of Opiorphin

Opiorphin(Gln-Arg-Phe-Ser-Arg-OH)is a new small peptide isolated from human saliva.It potentates bioactivities of endogenous opioid peptides by inhibiting two enkephalin-inactivating zinc ectopeptidases,neutral ecto-endopeptidase(NEP) and ecto-aminopeptidase(APN),such as painkilling,antidepressant and so on.It is up to six times more potent than morphine in rat.This work studied the structure of Opiorphin using nuclear magnetic resonance spectroscopy and molecular dynamics.Opiorphin was synthesized by solid phase peptide synthesis.After analysis of the chemical shifts of ¹H,³JNαand NOE,we conclude that Opiorphin exist mainly as random coil in DMSO-d₆.We also simulated the conformation of Opiorphin in water used the molecular dynamics computational method,the results suggested that Opiorphin exist mainly as flexible random coil in water too.This conformation may be the fit one before docking to its receptor,and maybe this random coil is suitable for their connection.Chapterâ… reviews basic knowledge of NMR and recent progresses in biomolecular NMR,which include TROSY experiments,proteinsplice,solid NMR, cryoprobe,LC-NMR and the applications of NMR in medicine.Chapterâ…¡provides the background of Opiorphin and the summary of this study. The zinc metallopeptidases and some nature inhibitor of zinc metallopeptidases, Opiorphin,were introduced,as well as the method of NMR in studying peptide.Chapterâ…¢introduces the solid phase synthesis of Opiorphin and NMR experiments.The sequence-specific assignment of spin systems and the complete assignment of proton resonances for backbone and side chain were introduced.Using NOE,³JNαand CSI analyzing suggests that Opiorphin exist mainly as random coil in DMSO-d6.Chapterâ…£introduces the molecular dynamics study of Opiorphin by GROMACS.Several stable conformations after energy minimization(EM),position restrained(Pr)and molecular dynamics(MD)were obtained.Analysis of the molecular conformation suggests that Opiorphin exist mainly as random coil in water. Chapterâ…¤provides the summary of this study,including the conclusion and deficiencies.