Biomedicine: CNR and Sapienza University identified key enzyme for bacterial survival
A study conducted by an international team coordinated by the Italian National Research Council, which involved scientists from the Sapienza University of Rome, has revealed why bacteria can breathe oxygen even in the presence of large amounts of hydrogen sulfide, a substance that impairs respiration in human cells. Bacteria’s secret weapon is cytochrome bd, a sulfide-resistant enzyme. The results of the study, which focused on Escherichia coli, were published in the journal Scientific Reports, by the Nature Publishing Group.
The well-known bacteria’s ability to adapt to extreme environmental conditions hostile to survival has been further confirmed. A recent study carried out by an international team of researchers coordinated by the National Research Council (CNR) revealed why the bacteria inhabiting the human gut are able to breathe oxygen and grow even in the presence of large amounts of hydrogen sulfide, a gas that impairs respiration in human cells.
The study, the results of which were published in the international journal Scientific Reports, by the Nature Publishing Group, involved scientists from the Institute of Molecular Biology and Pathology (IBPM) of CNR and from the Sapienza University of Rome, together with researchers at the Universities of Moscow, Lisbon, Sheffield and the Hospital for Sick Children in Toronto.
By studying Escherichia coli, bacteria frequently found in the human intestine, the researchers came to the conclusion that an enzyme – cytochrome bd – allows the bacteria to survive in such a hostile environment as the human intestine, characterized by the presence of large amounts of hydrogen sulfide. “Hydrogen sulfide (H2S) is a small gaseous molecule produced in large amounts by bacteria in our gut and can be easily recognized by the acrid smell”, explained Alessandro Giuffrè, IBPM-CNR researcher and coordinator of the study. “And it is a potent inhibitor of cell respiration, able to block the enzyme responsible for oxygen consumption in human cells. The aim of our study was to verify the hypothesis that some enzymes help the many bacteria present in our body to produce energy and survive, with important consequences for human health, despite the presence of the acid”.
The research team found that one of the two enzymes that enable the bacteria to breathe oxygen, cytochrome bd, is sulfide-resistant “The enzyme, present only in prokaryotic organisms like bacteria, allows them to consume oxygen and grow even in sulfide-rich environments, such as our gut”, added the IBPM-CNR researcher.
The next objective will be to develop drugs that are able to inhibit this enzyme. “Last month, Science published the crystallographic structure of the first cytochrome bd by Nobel Laureate Hartmut Michel”, said Giuffrè. “This will allow us to combine computational and experimental approaches aimed at the identification of effective and selective inhibitors that pave the way for the development of new generation antibiotics”.