“The unique connection between the Chlamydia bacterium and plants had been proposed by others,” said Thomas Leustek,” a professor in the department of plant biology and pathology at Rutgers' School of Environmental and Biological Sciences (formerly Cook College). “But we have now described a specific example demonstrating the common heritage. That specific example, an enzyme that supports protein production, could lead to antibiotics specific for this form of STD.”
The discovery is an unexpected turn in solving the mystery of how plants produce lysine, one of the 20 amino acids normally found in proteins. Scientists have known the specific pathways of lysine production in bacteria for more than a half-century. They also have known some of the steps by which lysine is produced in plants, but they didn’t really have the full picture. Leustek and Andre Hudson, a postdoc working in Leustek’s lab in Rutgers’ Biotechnology Center for Agriculture and the Environment, were able to solve the pathway when they discovered the gene encoding the enzyme L,L-diaminopimelate aminotransferase from the plant Arabdiopsis thaliana. The results of this discovery were published in the journal Plant Physiology in January 2006.
The gene that Leustek and Hudson had discovered was unmistakably similar to a sequence that Anthony Maurelli of the Uniformed Services University of the Health Sciences in Bethesda, Md., had detected in Chlamydia. “Further experimentation confirmed that the Chlamydial gene had the same function as the Arabidopisis gene demonstrating their common ancestry,” said Leustek. "If they evolved separately, it would be impossible for the sequences to match so closely.”
The ability to easily compare plants and bacteria is the result of genome sequencing, which has decoded the complete genetic blueprint for entire species. “This would not have been possible 10 years ago,” said Leustek. “But now we have access to more that 500 different genomes in a data base. After having identified a gene in plants, I can quickly identify the homologous gene from any bacteria in the database. As a plant biologist I wouldn’t have ever imagined that I would be working with Chlamydia. Yet, with the help of genomics I found myself working with a collaborator and publishing a paper in that area.”
Their experiments revealed that in addition to sharing genome sequences, Chlamydia and plants share similar functions as well. Furthermore, they found that the pathway used by plants to produce lysine is probably used by Chlamydia to synthesize a chemical found in bacterial cell walls. It is the synthesis of cell walls that is inhibited by penicillin. This discovery points to the likelihood that, if researchers could find an inhibitor for L,L-diaminopimelate aminotransferase they would have a new antibiotic that would target Chlamydia.
Chlamydia trachomatis is a bacteria that is responsible for a common STD. If untreated, Chlamydia infections can damage a woman's reproductive organs and lead to infertility. An estimated 2.8 million men and women in the U.S. are infected with chlamydia each year. Chlamydia can be easily treated and cured with antibiotics. However, bacteria often develop resistance to antibiotics, meaning that new ones must be continually discovered. Moreover, an inhibitor to L,L-diaminopimelate aminotransferase would be very specific for Chlamydia since this enzyme has not been found in any bacteria that live with humans.
So the hunt for a new antibiotic is on. Leustek is going to start screening for chemicals that block the enzyme. He is also using the results of his research to work on another approach, which is to characterize the structure of the enzyme so that he could design an antibiotic that would disable the pathway. This approach is somewhat like designing a key to fit a lock by opening the lock and looking inside.
The research is being done in collaboration with Charles Gilvarg from Princeton University. “He’s the biochemist who characterized the lysine pathway back in the 1950s, and so he had intimate knowledge about the steps of the pathway,” said Leustek. “And he’s the one that alerted us to the fact that plants do it differently. This is still the case, with the exception of the Chlamydia bacterium.”
The latest work, which describes the similarities in the genetic sequences of Chlamydia and plants, will be published in the Proceedings of the National Academy of Sciences’ Online Early Edition the week of November 6, 2006. In addition to Leustek, Hudson, Maurelli and Gilvarg, authors include Andrea McCoy and Nancy Adams of the Uniformed Services University of the Health Sciences.Contact:
Michele Hujber | EurekAlert!
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Machine Engineering
17.01.2017 | Physics and Astronomy