Kdp-dependent Kplus homeostasis of the halophilic archaeon Halobacterium salinarum
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https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2007121710
https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2007121710
Title: | Kdp-dependent Kplus homeostasis of the halophilic archaeon Halobacterium salinarum |
Authors: | Strahl, Henrik |
Thesis advisor: | Prof. Dr. Karlheinz Altendorf |
Thesis referee: | Prof. Dr. Felicitas Pfeifer |
Abstract: | Halobacteria balance high external osmolality by the accumulation of almost equimolar amounts of KCl. Thus, steady Kplus supply is a vital prerequisite for life of these extreme halophiles. So far, Kplus was supposed to enter the cell only passively by use of potential-driven uniporters. However, the genome of the extreme halophilic archaeon Halobacterium sp. NRC-1 comprises one single operon containing the genes kdpFABC coding for homologs of the bacterial ATP-driven Kplus uptake system KdpFABC, together with an additional ORF so far annotated as cat3. Deletion of the kdpFABCcat3 genes led to a reduced ability to grow under limiting Kplus concentrations, whereas real-time RT-PCR measurements revealed both high induction rates and a transcriptional regulation of the Kdp system dependent on external Kplus concentration and growth phase. The synthesis of the high-affinity KdpFABC complex enables H. salinarum to grow under extreme potassium-limiting conditions of down to 20 µM Kplus. These results provide the first experimental evidence of ATP-driven Kplus uptake in halobacteria. The current opinion that Kplus homeostasis of H. salinarum is solely mediated via membrane potential-driven Kplus uniporters is obviously only one aspect of a more complex system. |
URL: | https://osnadocs.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2007121710 |
Subject Keywords: | Halobacterium; potassium uptake; KdpFABC; Cat3; universal stress protein |
Issue Date: | 14-Dec-2007 |
Submission date: | 14-Dec-2007 |
Type of publication: | Dissertation oder Habilitation [doctoralThesis] |
Appears in Collections: | FB05 - E-Dissertationen |
Files in This Item:
File | Description | Size | Format | |
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E-Diss734_thesis.pdf | Präsentationsformat | 1,49 MB | Adobe PDF | E-Diss734_thesis.pdf View/Open |
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