In popular science books, cells are often depicted as collections of complicated machinery strategically disposed in a factory setting. In fact, this picture tells us quite a lot about the molecular robots that mediate and regulate the assembly-line fabrication and intricate quality-control systems actually found in cells. These and other aspects of their “engineering” make living organisms what reductionists have always held them to be – surprisingly reliable and superbly functional biological super-machines – largely made of proteins.
Proteins account for about half the dry weight of most cells, but it is their structural diversity that makes them so versatile. Every higher organism makes tens of thousands of structurally and functionally different species of proteins. They provide structural support, catalyze chemical reactions, transport metabolites to sites where they are needed, form channels in cell membranes and pump ions back and forth, serve as surface receptors that recognize and respond to signal molecules secreted by other cells. In short, proteins are both end-products and machine tools.
From isolated molecule to integrated network
Proteins are the dominant molecules of life, but many details of their function remain poorly understood, particularly with respect to their integration into functional networks. Researchers at LMU‘s Center for integrated Protein Science Munich wish to understand the structure of proteins and their workings at all levels of organization, from their basic properties as isolated molecules to their interactions and functions within the cell as a whole.
The CiPSM is a collaborative venture set up in 2006 with funding from the Excellence Initiative, which continues to support it. Some 25 scientists and their research groups form its core membership, and about 25 other groups are associated with the Center. The latter are based at the Technische Universität München, the Helmholtz Center Munich and the Max Planck Institute for Biochemistry in Martinsried.
The workings of molecular machines
The network is organized into six research units, each of which investigates a different facet of protein science, as Thomas Carell, Professor of Organic Chemistry at LMU and Speaker for the Excellence Cluster, explains. They analyze the structures and conformational dynamics of specific proteins using theoretical and biophysical methods. They study their biosynthesis, transport and degradation. They probe how multiprotein complexes, appropriately referred to as molecular machines, work and how they are regulated in the context of dynamic networks of interaction. Another focus concerns how proteins interact with DNA. How do organisms control the course of embryonic development and adapt to changing conditions by targeted modification of proteins after their synthesis? The research teams also use chemical methods to explore how biomolecules can be modified in useful ways, and employ model organisms to understand how proteins form functional networks, such as the organized reaction cascades that mediate signal transduction. (Kathrin Burger, Translation: Paul Hardy)
Pictures: (Source: Jan Greune, www.lmu.de)
Further reading: http://www.uni-muenchen.de/aktuelles/pdf/cm_insight_13-01.pdf