1.Synthesis And Physiological Activity Analysis Of The Mutants Of Hainantoxin-Ⅳ 2.Proteomic Analysis Of The Plasma Membrane Proteins From Rat Dorsal Root Ganglion Neurons

Part I :Synthesis and Physiological Activity of Mutants of Hainantoxin-IVHainantoxin-IV (HNTX-IV) purified from the venom of the spider Selenocosmia hainana Wang is a potent antagonist that acts on tetrodotoxin-sensitive (TTX-S) sodium channels. It is a 35-residue polypeptide and includes three disulf ide bridges. In order to investigate the structure-function relationship of HNTX-IV, two mutants (S12A and R29A) of HNTX-IV, in which Serl2 and Arg29 were replaced by Ala respectively, were synthesized by solid-phase Fmoc chemistry. Purified by reversal phase HPLC were refolded under different reaction conditions. The best renaturation yield was achieved in 0. 1 mmol/L Tris-HCl buffer (pH7. 4) containing 5 mmol/L GSH , 0. 5 mmol/L GSSG and 0. 1 mmol/L NaCl. MALDI-TOF mass spectrometric analysis indicates that the molecular weight of S12A-HNTX-IV and R29A-HNTX-IV are 3972. 95Da and 3903. 13Da respectively, which are 6 less than those of their corresponding reduced form, suggesting that the 6 cysteins formed three disulfide pairings.