Proteomics

Proteomics (English proteomics ) is the study of the proteome with biochemical methods. The proteome encompasses all present in a cell or an organism under defined conditions and at a defined time proteins. The proteome and the transcriptome are in contrast to the more static genome dynamic and can therefore in their qualitative and quantitative protein composition by changing conditions ( environmental factors, temperature, gene expression, drug administration, etc.) change. Very visually you can lead the dynamics of the proteome in the following example in mind. A caterpillar and the butterfly emerging from it contain the same genome, but still vary in appearance due to a different proteome. The same is true for a tadpole and the resulting frog. The changes in the proteome can be done in some cases very quickly - for example, by post-translational modifications such as phosphorylation and dephosphorylation of the proteins, which play a very important role in signal transduction.

Proteomics attempts to catalog all the proteins in the organism and to decipher their functions. The blueprints of the proteins found in the human genome. Saves the genetic material DNA only information, which consist of amino acids, protein molecules fulfill multiple tasks. They are basic substance of life and fend for example, as antibodies from disease and allow the enzymes including the metabolism and provide with skeleton, tendons and muscles for movement.

Definition

Major subdivisions are the elucidation of protein-protein interactions that depend mainly on the tertiary and quaternary structures of the proteins and the interactions of their domains. Further includes the protein purification, and a quantitative analysis of protein expression in the field of proteomics. This initiative complements the data obtained in gene expression analysis and provides information on the components of metabolic pathways and molecular control circuits. Protein engineering allows the variation of features of recombinant protein to adapt to its characteristics.

The key techniques of proteomics therefore support the elucidation of the function and the 3- D protein structure and the identification of individual proteins in mixtures.

Applications

Since all metabolic processes carried out by proteins based therapeutic approaches such as new drugs against cancer, infections and certain nervous diseases it. Conditions such as sickle cell anemia, Alzheimer 's disease, Huntington's disease or Creutzfeldt -Jakob disease based on faulty shaped and clumping proteins. Is therefore known, which protein is responsible for a malfunction, it is possible to selectively develop a small molecule that binds to said protein and preventing further malfunction. In industry recombinant proteins in the form of detergent enzymes and biological pesticides are used. Biologists hope to gain better insights into the functioning of living organisms and life as such. The biophysicist expect a " molecular anatomy ".

Issues and Trends

After partly sobering experiences with genetic methods, such as microarray analysis, there is also some scientists regarding the proteome before a certain skepticism. Friedrich Lottspeich at the Max Planck Institute for Biochemistry in Martinsried, President of the German Society for Proteome Research ( DGPF ) warns against exaggerated hopes: " For human use, research is currently actually anyway still too complex [ ... ] But for an analysis of the yeast that would be a good model system naturally wants to again spend any money. "

The complexity arises from the many possibilities: According to Friedrich Lottspeich man has an estimated several hundred thousand to millions of different proteins. A single gene produced an average of five to ten proteins, in some cases, several hundred. To fully capture this complexity is a challenge that have not yet grown the current methods. On the other hand, the proteome is evolving rapidly. This is mainly due to the continual development of the mass spectrometer, which are more precise, more sensitive and faster.

Another important step is the development of quantitative methods such as those based on the use of stable isotope SILAC, iTRAQ, TMT or ICAT method, or MeCAT metal encoding, are used in the different heavy metals for labeling proteins and peptides from different protein samples. The latter allows for the first time in the multiplex approach the proteome use of ultra -sensitive element mass spectrometry ( ICP -MS) ( limit of detection in the ppt to low ppq range), which allows a 2 to 5 orders of magnitude higher sensitivity for protein quantification and a linear dynamic range of at least 6-8 orders of magnitude having. MeCAT allowed, in contrast to other methods, the 'only' relatively quantified on peptide level, preferably a relative and even absolute quantification at the protein level, whereby protein species such as post-translationally modified proteins quantification are more accessible. Calibration of the ICP -MS is performed with protein-/peptidunabhängigen metal standards. Thus the need for protein -specific standard peptides omitted.

Combining quantitative proteomics with other biological methods, so you can also statements about the function of proteins meet (eg protein -protein interactions or post-translational modifications ). The modern proteomics therefore now goes far beyond the mere cataloging of proteins and attempts to understand complex mechanisms.

Research priorities HUPO and DGPF

Much like the Human Genome Organization ( HUGO ), the researchers of the International Humanproteom organization HUPO share the resulting work worldwide. Germany focuses on the study of brain proteins. In Germany, since 2001 leading protein and Proteomikwissenschaftler also in the German Society for Proteome Research ( DGPF ) come together to make optimal use of the research capacities.

Systems Biology

A new research area, which is based on proteomics, is systems biology. This does not try to look at the individual parts alone, for example, a cell, but also tries the interaction of all components within a system and its environment to describe. These are required in addition to the proteomics esp. mathematical models that simulate the system in silico.

Trivia

The word proteome comes from Australian researchers Marc Wilkins and has been on a slide in his presentation at the congress " 2D Electrophoresis: from protein maps to genomes " mentioned on September 5, 1994 relating to Siena for the first time. The text on the slide was " proteomes. Complement the protein overexpressed by a genome, cell or tissue " Translated " proteome: the PROTEinkomplement which is expressed from the genome of a cell or tissue ." The Congress will be held under the direction of Luca Bini every two years still (as of 2012) and since the famous slide by Marc Wilkins says: From Genome to Proteome.