FWF - Proteine Vitamin B6 - Proteins in a novel vitamin B6 biosynthetic pathway

Vitamin B6 (pyridoxine) is an essential nutritional compound required by animals and humans, which lack the biosynthetic pathway for its production. Only bacteria, fungi and plants possess the capability to synthesize vitamin B6 from basic suger components. The chemistry and biochemistry of the vitamin B6 biosynthesis has been studied in depth in the model bacteria Escherichia coli and it has been thought that this pathway is shared by all other organisms in which vitamin B6 biosynthesis occurs. In recent years, however, it emerged that the biosynthetic pathway found in E. coli is limited to a small group of eubacteria (chiefly the gamma-subdivision) and the majority of organisms have developed an entirely different route to generate vitamin B6. This novel biosynthetic pathway is the subject of our research proposal. In our studies we will focus on two new proteins that appear to be associated with the functioning of vitamin B6 biosynthesis in the prokaryote Bacillus subtilis: YaaD and YaaE. Their role in biosynthesis, however, is unknown and a major goal of our studies will be to unravel their function as regulators and/or enzymes in the pathway. In order to achieve this, both proteins will be cloned, heterologously expressed in a suitable host, followed by purification of the proteins for biochemical, biophysical and structural studies. YaaD has also been implicated as a regulator of oxygen stress response and the biosynthesis of vitamin B1 (thiamine). In order to understand the molecular basis of its role, we will aim to elucidate protein-protein interaction partners of YaaD with a view to define its role as a regulator/ modulator of other metabolic processes. Clearly, as both YaaD and YaaE are essential for vitamin B6 biosynthesis these two proteins may also provide interesting new drug targets for the development of antibiotics, fungicides and herbicides. In order to exploit these possible targets a detailed understanding of their role(s) as regulators, enzymes and/or modulators of proteinprotein interactions is required. Our research effort will provide the biochemical and biophysical basis to initiate a drug design/screening program which will receive additional support from the elucidation of the three-dimensional structures of our target proteins.