Life, microbe, plant or human, are all made up of atoms, which include metals such as copper and manganese which act as catalysts in proteins, which in turn around the metal atoms.
In their study, the researchers had shown that copper and manganese protein wrap around the correct metal atoms in different parts of the cell, which are zones containing different metals. Thus, which protein attaches to which metal is determined by where the folding action takes place in the cell.
Earlier scientists believed that the right metals were simply those, which were most attracted to the protein, but the new study led by Professor Nigel Robinson at Newcastle University, might change this perception.
"This has taken us one step closer to understanding why metals and proteins assemble in the ways they do," Nature quoted Robinson as saying.
He added: "One motive behind the work is pure curiosity, but as so many proteins need metals this type of work has many potential uses - for example, in synthetic biology which is striving to produce green power from bacteria by using energy from sunlight to produce hydrogen gas, a process which needs nickel and iron.
"It may also help in diseases such as Alzheimers where there are unexplained links to proteins binding metals such as copper. There's also application in controlling infections by Staphylococcus aureus; a bacterium which our bodies defences succeed - or sometimes fail - in killing by removing manganese and zinc from abscesses."
In the study, it was demonstrated that the way the metals attach is identical for a protein that binds manganese to one that binds copper. In both cases the metals bind inside protein barrels with the same type of metal-attractions.
The researchers carried out the work in a blue-green algae, a cyanobacterium, and showed that a protein requiring copper transports to the periplasm, the outer area of the cell, where it then folds around the available metal, which is copper.
On the other hand, manganese and not copper atoms are found in the cytosol, in the middle of the cell. They showed that a protein requiring manganese folds in the cytosol. The manganese protein is then transported to the periplasm having first trapped its manganese.
In the new study, the researchers first developed a new approach to discover metal-binding proteins, which is now being swiftly applied to lots of other types of living cells and other essential metals (zinc, nickel, cobalt, iron).
The study is published in the recent issue of Nature.