Shedding new light on enzyme crucial to life processes


Researchers at the University of Liverpool have revealed the crystal structure of a bacterial enzyme that offers clues on how electrons in the body move from one protein molecule to another.

The movement of electrons is called electron transfer (ET) and is essential for all living organisms, as it underpins processes such as respiration, photosynthesis, and detoxification. 

Scientists at Liverpool have examined the structure of a natural complex of the electron donor domain and the enzyme, called nitrite reductase, core.  The research sheds new light on the role it plays in electron transfer, as well as the production of nitric oxide, a direct precursor to nitrous oxide, which is an ozone-depleting and greenhouse gas, 300 times more potent than carbon dioxide.

Dr Svetlana Antonyuk, from the University’s Institute of Integrative Biology, explains: “The transfer of electrons between partner proteins is key to the functioning of all living things, but our understanding of how this process occurs is limited.

“The protein complexes are very transient in nature so it is not easily possible to obtain their crystals and use the powerful method of crystallography to image them.  Our system offered major advantage as it had both the donor and acceptor proteins fused together naturally.

“A striking feature of the structure is its extensive water network.  Several studies have suggested the importance of water molecules in mediating transfer of electrons, but our research demonstrates it.

“In order to carry out this research we used some of the most intense X-ray synchrotron radiation sources including facilities in Oxfordshire and in Paris. The provision of these state-of-the art facilities was critical in obtaining the high resolution of the structures of this tethered complex and allowed us to see every atom in the molecule.

“Our findings will provide important fundamental insight into life processes.”

The research is funded by the Biotechnology and Biological Science Research Council (BBSRC), and published in Nature.

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