Featured Research

from universities, journals, and other organizations

Acid levels control formic acid metabolism in bacterium

Date:
April 15, 2011
Source:
Albert-Ludwigs-Universität Freiburg
Summary:
Formate, the salt of formic acid, is an important product of metabolism in bacteria and -- in contrast to human metabolism -- a preliminary stage of the gas carbon dioxide, which is released in the combustion of sugar. Enterobacteriaceae, a large family of bacteria, possess the formate channel FocA, a specialized transport protein that transports the negatively charged ion of the formic acid over the cell membrane of the bacteria. Now researchers have succeeded in isolating and crystallizing FocA from the bacterium Salmonella typhimurium at a low pH value.

The formate channel FocA, a membrane protein.
Credit: Institute of Organic Chemistry and Biochemistry, University of Freiburg

Formate, the salt of formic acid, is an important product of metabolism in bacteria and -- in contrast to human metabolism -- a preliminary stage of the gas carbon dioxide, which is released in the combustion of sugar. Enterobacteriaceae, a large family of bacteria including the intestinal bacterium Escherichia coli as well as pathogens like Vibrio cholerae and Salmonella typhimurium, possess the formate channel FocA, a specialized transport protein that transports the negatively charged ion of the formic acid over the cell membrane of the bacteria.

Related Articles


The distinctive feature of the channel protein is a switching mechanism for closing that is triggered by a drop in the extracellular pH value: When the pH value is high, the protein functions as a passive channel that allows formate anions to flow out of the cell, whereas a drop in pH value makes the protein into a pump that actively takes in formate from the environment.

Dr. Wei Lü and Juan Du from the research group of Prof. Dr. Oliver Einsle, Institute of Organic Chemistry and Biochemistry of the University of Freiburg, succeeded in isolating and crystallizing FocA from the bacterium Salmonella typhimurium at a low pH value. In a joint project with Tobias Wacker from the Emmy Noether Junior Research Group of Dr. Susana Andrade from the same institute, the researchers observed directly how these channels close at a low pH value, a process that was previously only postulated.

A dual function of this kind has never been observed before in any transport protein. The highly dissolved space structure of the pentameric protein shows how the end of the protein chain places itself across the entire transport channel stretching over the bacterial membrane, thus blocking it and preventing the formate ions from passing through the membrane. At high pH values, where FocA functions as a passive channel, these protein domains are in disorder. The researchers integrated FocA into artificial membranes in the laboratory. Electrodes were used to measure the electric current created by the transport of the formate ions at various pH values.


Story Source:

The above story is based on materials provided by Albert-Ludwigs-Universität Freiburg. Note: Materials may be edited for content and length.


Journal Reference:

  1. W. Lu, J. Du, T. Wacker, E. Gerbig-Smentek, S. L. A. Andrade, O. Einsle. pH-Dependent Gating in a FocA Formate Channel. Science, 2011; 332 (6027): 352 DOI: 10.1126/science.1199098

Cite This Page:

Albert-Ludwigs-Universität Freiburg. "Acid levels control formic acid metabolism in bacterium." ScienceDaily. ScienceDaily, 15 April 2011. <www.sciencedaily.com/releases/2011/04/110415084952.htm>.
Albert-Ludwigs-Universität Freiburg. (2011, April 15). Acid levels control formic acid metabolism in bacterium. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2011/04/110415084952.htm
Albert-Ludwigs-Universität Freiburg. "Acid levels control formic acid metabolism in bacterium." ScienceDaily. www.sciencedaily.com/releases/2011/04/110415084952.htm (accessed October 24, 2014).

Share This



More Plants & Animals News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) — Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) — Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) — One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) — Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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