Abstract:

Tetridotoxin(TTX)、Sexitoxin(STX) are important tool-drugs in clarifing the sodium channel structure. The parameters of electronic structure、 molecular geometry and molecular coallguration of TTX、STX. and its derivatives were studied.
It is shown that active guanidinium group and hendketal ring in TTX and two guanidininm grouop in STX form two high polar planar orthoriangle coallguration with a positive net charge carbon centers. Three apices nitrogen or oxygen atoms of triangle posses strong negative charge respectively. Molecular electrostatic potential of some active site of TTX. STX and its derivatives were calculated and electrostatic potential contour maps were obtained. The fitting of TTX and STX molecular structres made by technology of molecular graphics shows very similar electronic and stereo characteristics both in TTX and STX. The acting mechanism and relationship between the molecular configurations and the toxicities of TTX, STX. and its derivatives were discuseed.

Key words: Marine toxin, Sodium channel, Quantum chemistry, Molecular graphics