A collaboration between researchers in Switzerland, the UK and France has led to the solution of the first crystal structure of a member of the Rhesus protein family and thereby shed new light on a group of proteins of great importance in human transfusion medicine. The UK group was led by Professor Mike Merrick in the Department of Molecular Microbiology at the John Innes Centre.
Ammonium is a fundamental source of nitrogen for almost all living cells but in excess it can also potentially be toxic. Bacteria, fungi and plants take up ammonium using proteins, called Ammonium Transport (Amt) proteins, which span the membranes of cells. Animals use a related family of proteins, known as the Rhesus (Rh) proteins, to move ammonium across cell membranes. In humans the Rh proteins are also responsible for the Rhesus negative blood type found in 15% of the human population.
Work on the mode of action of the Amt proteins has been pioneered by studies in the laboratory of Professor Mike Merrick in the Department of Molecular Microbiology at JIC. In collaboration with researchers at the Paul Sherrer Institute in Switzerland and France’s Université Paris Descartes and Institut Jacques Monod, Prof. Merrick’s group have now taken advantage of the fact that a Rhesus protein has been found to be made by a bacterium, Nitrosomonas europaea. Publishing in the journal Proceedings of the National Academy of Sciences of the U.S.A. Online Early Edition they have determined at very high resolution (1.3 Å), the first X-ray crystal structure of a Rhesus protein. This offers important insights into how these proteins facilitate the movement of ammonium across cell membranes. It also gives new information about the likely structure of these clinically important proteins in humans. For instance, this research strongly suggests that the equivalent human proteins are likely to be trimers and not tetramers as previously proposed.
Notes for Editors
The 1.3-Å resolution structure of Nitrosomonas europaea Rh50 and mechanistic implications for NH3 transport by Rhesus family proteins Domenico Lupo, Xiao-Dan Li, Anne Durand, Takashi Tomizaki, Baya Cherif-Zahar, Giorgio Matassi, Mike Merrick, and Fritz K. Winkler www.pnas.org/cgi/doi/10.1073/pnas.0706563104
About the John Innes Centre
The JIC, Norwich, UK is an independent, world-leading research centre in plant and microbial sciences with over 800 staff. JIC carries out high quality fundamental, strategic and applied research to understand how plants and microbes work at the molecular, cellular and genetic levels. The JIC also trains scientists and students, collaborates with many other research laboratories and communicates its science to end-users and the general public. The JIC is grant-aided by the Biotechnology and Biological Sciences Research Council. http://www.jic.ac.uk
Paul Sherrer Institut: http://www.psi.ch/
Université Paris Descartes: http://www.univ-paris5.fr/
L'Institut Jacques-Monod : http://www.ijm.fr
About BBSRC
The Biotechnology and Biological Sciences Research Council (BBSRC) is the UK funding agency for research in the life sciences. Sponsored by Government, BBSRC annually invests around £380 million in a wide range of research that makes a significant contribution to the quality of life for UK citizens and supports a number of important industrial stakeholders including the agriculture, food, chemical, healthcare and pharmaceutical sectors. BBSRC carries out its mission by funding internationally competitive research, providing training in the biosciences, fostering opportunities for knowledge transfer and innovation and promoting interaction with the public and other stakeholders on issues of scientific interest. For more information on BBSRC go to: www.bbsrc.ac.uk
Journal
Proceedings of the National Academy of Sciences