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 April 19, 2015 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 April 19, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, April 19, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Reuters - US Online Video (Apr. 17, 2015) — A truck carrying honey bees overturns near Lynnwood, Washington, spreading boxes of live bees across the highway. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Our Love Of Puppy Dog Eyes Explained By Science

Our Love Of Puppy Dog Eyes Explained By Science

Newsy (Apr. 17, 2015) — Researchers found a spike in oxytocin occurs in both humans and dogs when they gaze into each other&apos;s eyes. Video provided by Newsy
Powered by NewsLook.com
Dog Flu Spreading in Midwestern States

Dog Flu Spreading in Midwestern States

AP (Apr. 17, 2015) — Dog flu is spreading in several Midwestern states. Dog daycare centers and veterinary offices are taking precautions. (April 17) Video provided by AP
Powered by NewsLook.com
Raw: Rare Whale Spotted in Gulf of Mexico

Raw: Rare Whale Spotted in Gulf of Mexico

AP (Apr. 17, 2015) — Researchers from the E/V Nautilus had quite a surprise Tuesday, when a curious sperm whale swam around their remotely operated vehicle in the Gulf of Mexico. Cameras captured the encounter. (April 17) 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:

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