Study leader Frank Schroeder, a scientist at Cornell's Boyce Thompson Institute and Department of Chemistry and Chemical Biology, says that his team has discovered chemicals known as sulfated nucleosides, which are based on one of the building blocks of RNA, a molecule in living cells that helps build proteins.
A seemingly minor switch in an RNA component appears to contribute to the venom's toxic properties, he adds.
The researcher has revealed that this discovery results from an analysis of venom samples from more than 70 different types of spiders, including black widows and three members of the deadly recluse family: the Arizona, desert and brown recluse spiders.
According to him, two high-tech methods -- proton nuclear magnetic resonance spectrometry and mass spectrometry -- were used to look at the molecular structure of compounds.
The researchers observed that the venoms of black widow and recluse spiders, which equally terrify most people, were very different.
"Our results show that black widow venom does not contain sulfated nucleosides," Discovery News quoted Schroeder as saying.
The researcher instead says that one of the hourglass-marked spider's most important venom ingredients is the deadly neurotoxin latrotoxin that can invade its victim's cardiovascular system, muscles, and nervous system.
"(The research) nicely demonstrates that molecules can be identified from mixtures without the often large amount of work involved in purification," said Arthur Edison, director of the Advanced Magnetic Resonance Imaging and Spectroscopy Facility and an associate professor at the University of Florida.
He insisted that the spectrometry method might be the best way to study such venoms because conventional purification methods could destroy the newly identified compounds.
Schroeder said that he would create synthetic versions of the venoms, for use in future studies.