Glass full of genes
Completely unknown proteins to be encrypted using a new form of genome analysis
Researchers have found hundreds of thousands of genes in a glass of seawater, the functions of some of which are completely unknown. The aim of the new project led by Jun. Prof. Dr. Lars Leichert at the Medizinische Proteom Center of the RUB is to discover just what their secret is.
This Bochum scientist has received the European Research Council’s “Starting Grant” amounting to 1.5 million Euros for his research project. “We are following a completely new approach, as for the first time we are looking specifically for the functions of complete protein families”, Leichert explains. “For example, we test whether the proteins found in the sea water might be interesting for industry, such as for producing organic fuel or detergents.”
Testing proteins for industrial usability
The genome data which Leichert is working with originates from Craig Venters “Global Ocean Sampling” project. Over 17 million genes were found in sea water and 20% of them are completely new. “We don’t know which organism they come from or what their function could be, because they don’t look like any other genes we know”, Leichert explains. The scientists from Bochum now want to create a so-called expressions library. They do this by incorporating one of the unknown genes into e.coli, where it is transformed into a protein.
Ability to swim indicates protein function
Swim essay: Normal e.coli bacteria with the bacteria’s own oxidoreductase enyzyme can swim and spread out in the Petri dish (left). If you remove the enzyme, the bacteria cannot move away from the centre of the dish (middle). The ability to swim can then be re-introduced by adding an oxidoreductase from an unknown marine organism to e.coli (right). Images from Sebastian Nilewski
From this huge data pool the scientists have selected 1300 protein families and they are testing one representative member from each. They are not only looking for enzymes which can be used for industrial purposes but also for so-called oxidoreductases. These enzymes protect cells from damaging oxygen species which, among other things, trigger the aging process. In order to discover them among the unknown proteins, the Bochum scientists use an e.coli strain which does not produce its own oxidoreductases. Bacteria with mutations like this cannot swim on their own as the oxidoreductases are needed for the development of flagella for swimming. If the researchers put an unknown protein into the bacteria and these then swim, it is clear that the protein must be an oxidoreductase. Another target for the future is to create a whole collection of bacteria, each with one new protein, which other researchers can then continue to investigate, a clone library.