Featured Research

from universities, journals, and other organizations

Researchers Successfully Force Evolutionary Leap

Date:
February 23, 2004
Source:
University Of Texas At Austin
Summary:
Engineers and scientists at The University of Texas at Austin and the University of Michigan have forced an unprecedented evolutionary leap in E. coli bacteria, and findings from their study could have ramifications on protein production for the biotechnology industry.

Engineers and scientists at The University of Texas at Austin and the University of Michigan have forced an unprecedented evolutionary leap in E. coli bacteria, and findings from their study could have ramifications on protein production for the biotechnology industry.

The development, reported in the Feb. 20 issue of Science, demonstrated how the bacterium created an entirely new way to make disulfide bonds. These bonds compose a protein’s stiffening struts that helps the protein fold into its proper, functional, three-dimensional shape. Improperly folded proteins are implicated in diseases ranging from mad cow disease to Alzheimer’s disease.

“We were able to make evolution work for us,” says Dr. George Georgiou, professor of chemical engineering and biomedical engineering at The University of Texas at Austin, and a lead author of the paper. “It illustrated the remarkable diversity of biological systems that can result from a small number of mutations.”

In a process similar to natural selection, Dr. Georgiou and graduate student Lluis Masip made random alterations in the DNA of a strain of mutant bacteria developed by Dr. James Bardwell, an associate professor of molecular, cellular and developmental biology at the University of Michigan. Masip forced the bacteria to use the protein thioredoxin, which normally destroys disulfide bonds, to change its role and create the bonds.

The result required a surprisingly small change in thioredoxin’s make-up, says Masip. Only two amino acid changes, or a 2 percent change in the total number of amino acids in thioredoxin, restored the disulfide bond. The new thioredoxin could later form disulfide bonds using its new artificially-produced pathway, using none of its original disulfide bond mechanisms.

Georgiou, known for his work with antibodies that yielded a potential cure for anthrax, discussed this thioredoxin experiment at a scientific meeting in France in spring 2002, where Bardwell asked if they could collaborate to determine the mutant bacteria’s precise cause for success.

With post-doctoral fellow Jean Francois Collet, Bardwell's team found that the two amino acid substitutions in thioredoxin cause a remarkable transformation: they result in the binding of two iron and two sulfur atoms that form a complex that bridges two thioredoxin protein molecules. This iron-sulfur cluster was shown to be necessary for the new enzyme to form disulfides. Iron-sulfur complexes occur in many enzymes, but never before had such a functional iron-sulfur complex been introduced into a protein as a result of laboratory evolution. James Penner-Hahn, a professor of chemistry and chair of the Biophysics Research Division at U-M, showed exactly what kind of iron-sulfur cluster was involved.

Bardwell likens the new pathway for disulfide bond formation to engineering."People often speak of computer-assisted design, where you try things out on a computer screen before you manufacture them,” he said. “We put the bacteria we were working on under a strong genetic selection, like what can happen in evolution, and the bacteria came up with a completely new answer to the problem of how to form disulfide bonds. I think we can now talk about genetic-assisted design.

"The naturally occurring enzymes involved in disulfide bond formation are a biological pathway whose main features are the same from bacteria to man," Bardwell said. "Understanding how disulfide bond formation occurs and figuring out new ways to make it happen could be important to numerous disease states, like Alzheimer's and cystic fibrosis, that result from defective protein folding."

Disulfides are also vital for the activity of most proteins injected into people for medical purposes, such as insulin and TPA, a blood clot dissolver injected into people having heart attacks and strokes.


Story Source:

The above story is based on materials provided by University Of Texas At Austin. Note: Materials may be edited for content and length.


Cite This Page:

University Of Texas At Austin. "Researchers Successfully Force Evolutionary Leap." ScienceDaily. ScienceDaily, 23 February 2004. <www.sciencedaily.com/releases/2004/02/040223075250.htm>.
University Of Texas At Austin. (2004, February 23). Researchers Successfully Force Evolutionary Leap. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2004/02/040223075250.htm
University Of Texas At Austin. "Researchers Successfully Force Evolutionary Leap." ScienceDaily. www.sciencedaily.com/releases/2004/02/040223075250.htm (accessed July 29, 2014).

Share This




More Plants & Animals News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
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