02.07.09 Prof. Michael Ehrmann, Uni Duisburg-Essen
Function and regulation of the conserved DegP/HtrA protease of E. coli
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| When |
02.07.2009 from 05:15 to 06:00 |
| Where | SR 1007, Albertstr. 21, 10. OG |
| Contact Name | Angelika Massler |
| Contact Phone | 203 6090 |
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The extracytoplasmic heat shock and virulence factor DegP not only switches reversibly between the active and inactive states but also between at least three distinct oligomeric conformations. Hexameric DegP represents the resting state. Misfolded proteins, protein fragments or mislocalized outer membrane proteins trigger dramatic conformational changes leading to the formation of 12 and 24meric particles that are enzymatically active. While the functional and structural plasticity of DegP was recently elucidated on the structural level, the underlying mechanisms are not well understood. A rational mutagenesis approach and refolding studies of chemically denatured DegPs revealed the triggering mechanism and identified several elements within DegP that drive the coordinated conformational changes required to build the various oligomeric structures and convert the inactive into the active enzyme. In addition, genetic evidence is presented for the functional interaction of DegP with other periplasmic folding factors and proteases. The implications for the mechanism of protein quality control are discussed.