Navigation Links
Team discovers how bacteria resist a 'Trojan horse' antibiotic
Date:3/19/2012

CHAMPAIGN, lll. A new study describes how bacteria use a previously unknown means to defeat an antibiotic. The researchers found that the bacteria have modified a common "housekeeping" enzyme in a way that enables the enzyme to recognize and disarm the antibiotic.

The study appears in the Proceedings of the National Academy of Sciences.

Bacteria often engage in chemical warfare with one another, and many antibiotics used in medicine are modeled on the weapons they produce. But microbes also must protect themselves from their own toxins. The defenses they employ for protection can be acquired by other species, leading to antibiotic resistance.

The researchers focused on an enzyme, known as MccF, that they knew could disable a potent "Trojan horse" antibiotic that sneaks into cells disguised as a tasty protein meal. The bacterial antibiotic, called microcin C7 (McC7) is similar to a class of drugs used to treat bacterial infections of the skin.

"How Trojan horse antibiotics work is that the antibiotic portion is coupled to something that's fairly innocuous in this case it's a peptide," said University of Illinois biochemistry professor Satish Nair, who led the study. "So susceptible bacteria see this peptide, think of it as food and internalize it."

The meal comes at a price, however: Once the bacterial enzymes chew up the amino acid disguise, the liberated antibiotic is free to attack a key component of protein synthesis in the bacterium, Nair said.

"That is why the organisms that make this thing have to protect themselves," he said.

In previous studies, researchers had found the genes that protect some bacteria from this class of antibiotic toxins, but they didn't know how they worked. These genes code for peptidases, which normally chew up proteins (polypeptides) and lack the ability to recognize anything else.

Before the new study, "it wasn't clear how a peptidase could destroy an antibiotic," Nair said.

To get a fuller picture of the structure of the peptidase, Illinois graduate student Vinayak Agarwal crystallized MccF while it was bound to other molecules, including the antibiotic. An analysis of the structure and its interaction with the antibiotic revealed that MccF looked a lot like other enzymes in its family, but with a twist or, rather, a loop. Somehow MccF has picked up an additional loop of amino acids that it uses to recognize the antibiotic, rendering it ineffective.

"Now we know that specific amino acid residues in this loop are responsible for making this from a normal housekeeping gene into something that's capable of degrading this class of antibiotics," Nair said.

With this information, researchers and eventually, doctors and other clinicians will be able to scan the genomes of disease-causing bacteria to find out which ones have genes with the antibiotic-resistance loop in them, Nair said. "If we know what type of bacteria are causing an infection we know what kind of antibiotic to give and what kind not to give," he said.

Nair is also an affiliate of the Center for Biophysics and Computational Biology, the department of chemistry and of the Institute for Genomic Biology at Illinois. The research team included scientists from the Russian Academy of Sciences and Rutgers University.


'/>"/>

Contact: Diana Yates
diya@illinois.edu
217-333-5802
University of Illinois at Urbana-Champaign
Source:Eurekalert  

Related biology news :

1. International team discovers gene associated with epilepsy
2. Texas A&M anthropologist discovers long-lost primate in Indonesia
3. Stowers Institutes Workman Lab discovers novel histone demethylase protein complex
4. UCSF discovers new glucose-regulating protein linked with diabetes
5. Biologist discovers pink-winged moth in Chiracahua Mountains
6. NTU professor discovers method to efficiently produce less toxic drugs using organic molecules
7. La Jolla Institute discovers novel tumor suppressor
8. IU discovers stone tools, rare animal bones -- clues to Caribbeans earliest inhabitants
9. Case Western Reserve University discovers Merkel cell originates from skin, not the neural crest
10. Iowa State University researcher discovers Ebolas deadly secret
11. CSHL-led team discovers rare mutation dramatically increasing schizophrenia risk
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Team discovers how bacteria resist a 'Trojan horse' antibiotic
(Date:1/13/2016)... 2016 http://www.researchandmarkets.com/research/7h6hnn/india_biometrics ... the  "India Biometrics Authentication & Identification ...  report to their offering.  ... the addition of the  "India Biometrics ... & Forecast (2015-2020)"  report to ...
(Date:1/8/2016)... MANCHESTER, United Kingdom , Jan. 8, 2016 /PRNewswire/ ... sensor-based diagnostic products, today announced the closing of a $9 ... investors.  Proceeds from the financing will be used to accelerate ... device for detecting early-stage pressure ulcers. ... after receiving CE Mark approval. The device,s introduction has been ...
(Date:1/7/2016)... 2016 Various factors have contributed to ... as biologics and biosimilars. Some of these factors ... growing demand for cost-effective alternatives, growing burden of ... similar versions of their corresponding patented biologic drugs, ... safety, and efficacy. The global biosimilars market is ...
Breaking Biology News(10 mins):
(Date:2/9/2016)... 9, 2016 This market research report on ... future prospects of the market in terms of revenue ... engaged in the manufacture of microbiology culture media and ... a market snapshot providing the overall information of various ... This section also provides the overall information and data ...
(Date:2/9/2016)... February 9, 2016 Three-Year Initiative Supports ... to Take Part in Life-Changing Camp ... designed to positively affect the lives of children born with rare ... --> SHPG ) is announcing a new initiative designed to ... well as the future of rare disease care. --> ...
(Date:2/9/2016)... DelveInsight,s, "Protein-Tyrosine Phosphatase ... in depth insights on the pipeline drugs ... Phosphatase 1B (PTP1B) Inhibitors. The DelveInsight,s Report ... of development including Discovery, Pre-clinical, IND, Phase ... Report covers the product clinical trials information ...
(Date:2/8/2016)... Feb. 8, 2016 Should antibiotic bone cement ... products to prevent infection after standard total hip or ... at ECRI Institute have been fielding a lot lately. ... Your Bottom Line?" --> "Antibiotic ... --> While there isn,t a ...
Breaking Biology Technology: