Featured Research

from universities, journals, and other organizations

How scorpion gets its sting

Date:
January 14, 2014
Source:
Molecular Biology and Evolution (Oxford University Press)
Summary:
A new study provides the first functional evidence for an evolutionary connection between insect defensins and scorpion -KTxs, and how one small genetic mutation leads to a new protein function to give scorpions their deadly sting.

Defensins, as their name implies, are small proteins found in plants and animals that help ward off viral, bacterial or fungal pests. One fascinating question of invertebrate evolution is how these proteins evolved into venoms to attack their prey.

Based on structural similarity, it was proposed that scorpion toxins and antimicrobial invertebrate defensins could have a common ancestor. To address how a nontoxic protein develops into a toxin, authors Zhu, et. al. studied the evolution of scorpion venom-derived neurotoxins, known as α-KTxs.

In a new study, published in the advanced online edition of Molecular Biology and Evolution, they analyzed the α-KTx family sequences to extract the conserved amino acid sites associated with neurotoxin structure and function (called "Scorpion Toxin Signature," abbreviated as STS). They searched for insect defensins that contain a STS to unlock the molecular mechanisms behind STS evolution. Their results show that a STS-containing insect defensin can be converted to the scorpion α-KTx-like neurotoxin through just a single genetic deletion event. The study provides the first functional evidence for an evolutionary connection between insect defensins and scorpion α-KTxs, and how one small genetic mutation leads to a new protein function to give scorpions their deadly sting.

"The most significant findings of our paper are the predictability of scorpion toxicity evolution -- arising via structural deletion of a loop on an ancestral defensin scaffold recruited into the venom to remove steric hindrance of peptide-channel interaction," said lead author Dr. Shunyi Zhu. "Our work represents an excellent example of divergent evolution, where structural alteration in an ancestral scaffold led to functional shift of proteins from fighting against microbes to attacking prey."


Story Source:

The above story is based on materials provided by Molecular Biology and Evolution (Oxford University Press). Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Zhu, S. Peigneur, B. Gao, Y. Umetsu, S. Ohki, J. Tytgat. Experimental Conversion of a Defensin into a Neurotoxin: Implications for Origin of Toxic Function. Molecular Biology and Evolution, 2014; DOI: 10.1093/molbev/msu038

Cite This Page:

Molecular Biology and Evolution (Oxford University Press). "How scorpion gets its sting." ScienceDaily. ScienceDaily, 14 January 2014. <www.sciencedaily.com/releases/2014/01/140114202909.htm>.
Molecular Biology and Evolution (Oxford University Press). (2014, January 14). How scorpion gets its sting. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2014/01/140114202909.htm
Molecular Biology and Evolution (Oxford University Press). "How scorpion gets its sting." ScienceDaily. www.sciencedaily.com/releases/2014/01/140114202909.htm (accessed September 18, 2014).

Share This



More Plants & Animals News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Chimp Violence Study Renews Debate On Why They Kill

Chimp Violence Study Renews Debate On Why They Kill

Newsy (Sep. 17, 2014) The study weighs in on a debate over whether chimps are naturally violent or become that way due to human interference in the environment. Video provided by Newsy
Powered by NewsLook.com
Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins