Bacteria shed light on an important group of human proteins

November 19, 2007

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.

Citation: 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

Source: Norwich BioScience Institutes

Explore further: Using artificial lipid vesicles, biochemists show how membrane proteins transport ammonium

Related Stories

New research resolve Rh protein's biological role

May 26, 2005

Labels marking bags of donated blood throughout the world contain information about the presence of a Rhesus (Rh) antigen, a protein found on the membranes of human red blood cells. Yet, despite the Rh protein's importance ...

Breakthrough: Sensors monitor cells at work

July 2, 2013

Transport proteins are responsible for moving materials such as nutrients and metabolic products through a cell's outer membrane, which seals and protects all living cells, to the cell's interior. These transported molecules ...

Recommended for you

Controlling ice formation

March 24, 2017

(Phys.org)—Researchers have demonstrated that ice crystals will grow along straight lines in a controlled way on microgrooved surfaces. Compared to the random formation of ice crystals on smooth surfaces, the ice on the ...

Study into who is least afraid of death

March 24, 2017

A new study examines all robust, available data on how fearful we are of what happens once we shuffle off this mortal coil. They find that atheists are among those least afraid of dying... and, perhaps not surprisingly, ...

Astronomers identify purest, most massive brown dwarf

March 24, 2017

An international team of astronomers has identified a record breaking brown dwarf (a star too small for nuclear fusion) with the 'purest' composition and the highest mass yet known. The object, known as SDSS J0104+1535, is ...

Inventing a new kind of matter

March 24, 2017

Imagine a liquid that could move on its own. No need for human effort or the pull of gravity. You could put it in a container flat on a table, not touch it in any way, and it would still flow.

In a quantum race everyone is both a winner and a loser

March 24, 2017

Our understanding of the world is mostly built on basic perceptions, such as that events follow each other in a well-defined order. Such definite orders are required in the macroscopic world, for which the laws of classical ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.