27. November 2007
First structure of a Rhesus family membrane protein solvedHuman Health Biology Research Using Synchrotron Light
Researchers at PSI, in collaboration with scientists in France and England, have solved the first structure of a Rhesus (Rh) protein and thereby shed new light on a group of proteins of great importance in human transfusion medicine. Transport of ammonium across cellular membranes is an important biological process and is regulated by special membrane spanning proteins when needed. Bacteria, fungi and plants use ammonium as nitrogen source and make use of Amt (ammonium transport) family proteins to enhance the ammonium uptake capacity under nitrogen starvation. Animals use a related family of proteins, known as the Rhesus (Rh) proteins, to move ammonium which is toxic in excess across cell membranes. In humans the Rh proteins are also responsible for the Rh+ blood type found in about 85% of the human population.
Publishing in the journal Proceedings of the National Academy of Sciences Online Early Edition the researchers have determined at very high resolution (1.3 Å), the X-ray crystal structure of the Rh protein from Nitrosomonas europaea using data from PSI's Swiss Light Source (SLS). 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 and how they are arranged in red blood cell membranes.