Study finds biochemical role of crucial TonB protein in bacterial iron transport and pathogenesis

July 1, 2013 by Greg Tammen
This image shows the localization of TonB (green) in E. coli cells. Credit: Phillip E. Klebba

(Phys.org) —A Kansas State University-led study has discovered the role of a protein in bacteria that cause a wide variety of diseases, including typhoid fever, plague, meningitis and dysentery. The results may lead to new and improved antibiotics for humans and animals.

Phillip E. Klebba, professor and head of the department of biochemistry and , made the findings with two colleagues in the department: Lorne D. Jordan, doctoral candidate, Manhattan, and Salete M. Newton, research professor. The collaboration included other biophysicists at the University of Oklahoma and Purdue University. Their study, "Energy-dependent motion of TonB in the Gram-negative bacterial inner membrane," appears in the journal Proceedings of the National Academy of Sciences, or PNAS.

The research focuses on the central role of iron in biochemistry. Both animals and bacteria require iron for biological processes like energy generation and DNA, Klebba said. The iron acquisition systems of bacteria, however, contribute to infectious diseases.

"Iron is the object of a microbiological war in the human body," Klebba said. "Host proteins defend cells and tissues by sequestering the metal, and successful pathogens overcome this barrier and capture the iron. But the mechanisms of are not well understood."

The membrane protein TonB plays an indispensable role in the uptake of iron by Gram-negative bacteria—a classification of bacteria that is more resistant to antibiotics because of a nearly impenetrable cell wall. Gram-negative bacteria can cause diseases such as Escherichia coli, Salmonella typhi, Yersinia pestis, Vibrio cholera, Brucella abortus, Neisseria meningitidis cause many diseases and clinical conditions; they all transport iron by the same mechanism that depends on the actions of TonB.

Despite decades of research, the biochemical role of TonB in Gram-negative bacteria was a scientific mystery, Klebba said. He and his colleagues found that the cellular electrochemical forces put TonB in a spinning motion that provides the energy and physical mechanism to enable iron uptake into the cell.

"In this sense TonB acts like an electric motor that constantly rotates in response to the cellular energy flow," Klebba said. "TonB is one of nature's smallest and oldest electrical devices."

According to Klebba, future antibiotics may block the functions of TonB, prevent iron acquisition by Gram-negative cells, and consequently protect humans and animals from infection by such pathogen strains of bacteria.

Besides the PNAS study, Klebba recently shared the findings at the 2013 Gordon Conference on Mechanisms of Membrane Transport in South Hadley, Mass.

Explore further: Scientists discover how some bacteria may steal iron from their human hosts

More information: www.pnas.org/content/early/2013/06/20/1304243110.full.pdf+html

Related Stories

Unique E. coli protein may be not after all

January 3, 2012

A bacterial protein recently thought to be a unique mechanism for utilizing iron may not be after all. Researchers from the University of Georgia, the Fellowship for Interpretation of Genomes, the University of Oklahoma and ...

Big, bad bacterium is an 'iron pirate'

February 21, 2012

(PhysOrg.com) -- Life inside the human body sometimes looks like life on the high seas in the 1600s, when pirates hijacked foreign vessels in search of precious metals.

Genes define the interaction of social amoeba and bacteria

May 9, 2013

Amoeba eat bacteria and other human pathogens, engulfing and destroying them – or being destroyed by them, but how these single-cell organisms distinguish and respond successfully to different bacterial classes has been ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

4 million years at Africa's salad bar

August 3, 2015

As grasses grew more common in Africa, most major mammal groups tried grazing on them at times during the past 4 million years, but some of the animals went extinct or switched back to browsing on trees and shrubs, according ...

A look at living cells down to individual molecules

August 3, 2015

EPFL scientists have been able to produce footage of the evolution of living cells at a nanoscale resolution by combining atomic force microscopy and an a super resolution optical imaging system that follows molecules that ...

New lizard named after Sir David Attenborough

August 3, 2015

A research team led by Dr Martin Whiting from the Department of Biological Sciences recently discovered a beautifully coloured new species of flat lizard, which they have named Platysaurus attenboroughi, after Sir David Attenborough.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.