Funktion und Struktur des Porins MspA von Mycobacterium smegatis

• Applicant: Professor Dr. Michael Niederweis
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 1997 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5390997

• Final Report Year: 2009

Final Report Abstract

Mycobacteria are gram-positive bacteria, yet their cell wall contains unusual lipids that constitute an efficient permeability barrier for small molecules. We also discovered MspA as the first porin of Mycobacterium smegmatis. While MspA is crucial for efficient uptake of small, hydrophilie solutes across the OM, the complete lack of porin activity is lethal for M. smegmatis. The crystal structure of MspA is the only structure of a mycobacterial outer membrane protein (OMP) to date. It revealed a novel protein fold and provided the proof of principle that mycobacterial OMPs have different structures than OMPs in gram-negative bacteria. Its extreme stability and favorable architecture make MspA an ideal protein for nanotechnological applications. These findings have been published in 12 papers in highimpact journals and laid the foundation for several successful follow-up projects that would not have been possible without the support by the DFG.

Publications

• (2003) High level expression of the mycobacterial porin MspA in Escherichia coll and purification of the recombinant protein. J. Chromatogr B 790, 337-348
  Heinz, C., Karosi, S. and Niederweis, M.
  
• (2003) Mycobacterial porins - new channel proteins in unique bacterial outer membranes. Mot. Microbiol. 49, 1167-1177
  Niederweis, M.
  
• (2003) The core of the tetrameric mycobacterial porin MspA is an extremely stable ß-sheet domain. J. Biol. Chem. 278. 8678-8685
  Heinz, C., Engelhardt, H. and Niederweis, M.
  
• (2004) Consecutive gene deletions in Mycobacterium smegmatis using the yeast FLP recombinase. Gene 343, 181-190
  Stephan, J., Stemmer, V. and Niederweis, M.
  
• (2004) DNA-free RNA preparation from mycobacteria. BMC Microbiology 4,45
  Stephan, J., Bail, J. G., Titgemeyer, F. and Niederweis, M.
  
• (2004) Multi-drug resistance of a porin-deletion mutant of Mycobactehum smegmatis Antimicrob. Agents Chemother. 48, 4163-4170
  Stephan, J., Mailaender, C., Etienne, G., Daffé, M. and Niederweis, M.
  
• (2004) The MspA porin promotes growth and increases antibiotic susceptibility of both Mycobacterium bovis BOG and Mycobactehum tuberculosis. Microbiology 150, 853-864
  Mailaender, C., Reiling, N., Engelhardt, H., Bossmann, S. H., Ehlers, S. and Niederweis, M.
  
• (2004) The structure of a mycobacterial outer membrane channel Science 303, 1189-1192
  Faller, M., Niederweis, M. and Schulz, G. E.
  
• (2005) Porins limit the intracellular persistence of Mycobactehum smegmatis. Microbiology 151, 2403-2410
  Sharbati-Tehrani, S., Stephan, J., Holland, G., Appel, B., Niederweis, M. and Lewin, A.
  
• (2005) The growth rate of Mycobacterium smegmatis depends on sufficient porin-mediated influx of nutrients. Mol. Microbiol. 58, 714-730
  Stephan, J., Wolschendorf, F., Bender, J., Hoffmann, C., Roth. E., Mailaender, C., Engelhardt, H. and Niederweis, M.
  
• (2006) Topology of the porin MspA in the outer membrane of Mycobactehum smegmatis. J. Biol. Chem. 281, 5908-5915
  Mahfoud, M., Sukumaran, S., Hülsmann, P., Grieger, K. and Niederweis, M.
  
• (2007) Expression of the major porin gene mspA is regulated in Mycobactehum smegmatis. J. Bacteriol. 189,958-967
  Hillmann, D., Eschenbacher, I., Thiel, A. and Niederweis, M.