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

Jul 01, 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: Researchers make significant step forward in combating antibiotic resistance

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

Related Stories

Big, bad bacterium is an 'iron pirate'

Feb 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.

Unique E. coli protein may be not after all

Jan 03, 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 ...

Recommended for you

Cell division speed influences gene architecture

2 hours ago

Speed-reading is a technique used to read quickly. It involves visual searching for clues to meaning and skipping non-essential words and/ or sentences. Similarly to humans, biological systems are sometimes ...

Secret life of cells revealed with new technique

4 hours ago

(Phys.org) —A new technique that allows researchers to conduct experiments more rapidly and accurately is giving insights into the workings of proteins important in heart and muscle diseases.

In the 'slime jungle' height matters

4 hours ago

(Phys.org) —In communities of microbes, akin to 'slime jungles', cells evolve not just to grow faster than their rivals but also to push themselves to the surface of colonies where they gain the best access ...

Queuing theory helps physicist understand protein recycling

Apr 22, 2014

We've all waited in line and most of us have gotten stuck in a check-out line longer than we would like. For Will Mather, assistant professor of physics and an instructor with the College of Science's Integrated Science Curriculum, ...

Cow manure harbors diverse new antibiotic resistance genes

Apr 22, 2014

Manure from dairy cows, which is commonly used as a farm soil fertilizer, contains a surprising number of newly identified antibiotic resistance genes from the cows' gut bacteria. The findings, reported in mBio the online ...

User comments : 0

More news stories

Ravens understand the relations among others

Like many social mammals, ravens form different types of social relationships – they may be friends, kin, or partners and they also form strict dominance relations. From a cognitive perspective, understanding ...

How many moons does Venus have?

There are dozens upon dozens of moons in the Solar System, ranging from airless worlds like Earth's Moon to those with an atmosphere (most notably, Saturn's Titan). Jupiter and Saturn have many moons each, ...

Precise control of optical frequency on a chip

In the 1940s, researchers learned how to precisely control the frequency of microwaves, which enabled radio transmission to transition from relatively low-fidelity amplitude modulation (AM) to high-fidelity ...