| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Papers In Press, published online ahead of print January 17, 2006
Institut für Biochemie, Universität zu Köln, Köln 50674
Corresponding Author: s.morbach{at}uni-koeln.de
The glycine betaine carrier BetP of C. glutamicum was recently shown to function both as an osmosensor and osmoregulator in proteoliposomes made from E. coli phospholipid by sensing changes of the internal K+ concentration as a measure of hyperosmotic stress. Furthermore, evidence was provided that a stretch of 25 amino acids of the C-terminal domain of BetP is critically involved in K+-sensing. This K+-sensitive region was further characterized. The glutamate residue at position 572 turned out to be important for osmosensing either in E. coli cells or in proteoliposomes made from E. coli phospholipids. BetP E572K, BetP E572P or BetP 572AAA (EHR572-574AAA) where unable to detect an increase of the internal K+ concentration in this membrane environment. These BetP variants, however, regained their ability to detect osmotic stress in membranes with increased phosphatidyl glycerol content, i. e. in intact C. glutamicum cells or in proteoliposomes mimicking the composition of the C. glutamicum membrane. BetP E572P or BetP Y550P, however, were still insensitive to osmotic stress also in this membrane background. These results led to the following conclusions. (i) The K+ sensor in the mutant proteins BetP E572Q, E572D and E572K is only partly impaired. (ii) Restoration of activity regulation is not possible if the correct conformation or orientation of the C-terminal domain is compromised by a proline residue at positions 572 or 550. iii) Phosphatidyl glycerol in the membrane of C. glutamicum seems to stabilize the inactive conformation of BetP C252T and the mutants.
J. Biol. Chem, 10.1074/jbc.M513052200
Submitted on December 7, 2005
Revised on January 13, 2006
Accepted on January 17, 2006
Influence of membrane composition on osmosensing by the betaine carrier BetP from Corynebacterium glutamicum
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  N. Ozcan, C. S. Ejsing, A. Shevchenko, A. Lipski, S. Morbach, and R. Kramer Osmolality, Temperature, and Membrane Lipid Composition Modulate the Activity of Betaine Transporter BetP in Corynebacterium glutamicum J. Bacteriol., October 15, 2007; 189(20): 7485 - 7496. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Zimmann, A. Steinbrugge, M. Schniederberend, K. Jung, and K. Altendorf The Extension of the Fourth Transmembrane Helix of the Sensor Kinase KdpD of Escherichia coli Is Involved in Sensing J. Bacteriol., October 15, 2007; 189(20): 7326 - 7334. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Tondervik and A. R. Strom Membrane topology and mutational analysis of the osmotically activated BetT choline transporter of Escherichia coli Microbiology, March 1, 2007; 153(3): 803 - 813. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. M. Wood Osmosensing by Bacteria Sci. Signal., October 17, 2006; 2006(357): pe43 - pe43. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. A. B. N. Mahmood, E. Biemans-Oldehinkel, J. S. Patzlaff, G. K. Schuurman-Wolters, and B. Poolman Ion Specificity and Ionic Strength Dependence of the Osmoregulatory ABC Transporter OpuA J. Biol. Chem., October 6, 2006; 281(40): 29830 - 29839. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| All ASBMB Journals | Molecular and Cellular Proteomics |
| Journal of Lipid Research | ASBMB Today |
