A group of CAS scientists have succeeded in purifying many conotoxins and cloning more than 100 new genes from six species of cone snails living in waters off the coast of the South China Sea, paving the way for the development of new drugs to relieve neuropathic pains. The work has been honored with a first prize from the 2005 Awards for S&T Progress in Shanghai.
The cone snail is a family (Conidae) of fish-, mollusk- or worm-eating marine gastropods, living in tropical coral reefs and associated habitats. They produce venom to paralyze preys before killing and eating them. The composition of the venom differs greatly between species. So far about 500 species of various cone snails have been identified, which are believed to be able to produce more than 50,000 different pharmacologically active components. Some conotoxins have shown potential for treating pains, epilepsy and other neuropathic disorders. They will be a promising treasure house for biological toxicants in addition to those of snakes, spiders and scorpions.
A research team headed by Prof. Qi Zhengwu, a CAS member from the Institute of Biochemistry and Cell Biology under the CAS Shanghai Institutes for Biological Sciences, has carried out penetrating studies on the protein structure, gene cloning and physiological functions of the conotoxins. They have been successful in identifying over 40 conotoxins and cloning of more than 100 new genes from different species of cone snails.
Although the conotoxins feature smaller molecules in comparison with other animal toxins, containing 10-40 amino-acids, says Prof. Qi, they are noted for their diversity and stable structure, easy to be synthesized and developed into new drugs with independent intellectual properties. Besides, conotoxins are highly specific, able to distinguish between nerve cells and muscle cells. This is to say, when used as a medication, a conotoxin tends to deal a telling blow more directly to the vital part and leaves no side effects.
According to informed sources, the Food & Drug Administration under the US Government has ratified a conotoxin to be used as a pain killer for advanced cancer sufferers, showing better analgesic efficacy than morphine derivatives without addiction. So far, Chinese researchers have actively joined the international community in this field.
