Halobacterium salinarum

Halobacterium salinarum Rapid expression Colorimetric expression Easy scale-up Cloning and transformation complicated Requires fusion protein strategy Lack of post-translational modifications 

coli Rapid cloning procedure High expression levels Easy scale-up Toxicity of foreign membrane proteins Lack of post-translational modifications 

---

Indeed, hydrophilic N- or C-terminal ends and loop domains of these membrane proteins exposed to aqueous phases are able to undergo rapid or intermediate motional fluctuations, respectively, as shown in the 3D pictures of transmembrane (TM) moieties of bacteriorhodopsin (bR) as a typical membrane protein in the purple membrane (PM) of Halobacterium salinarum.176 178 Structural information about protein surfaces, including the interhelical loops and N- and C-terminal ends, is completely missing from X-ray data. It is also conceivable that such pictures should be further modified, when membrane proteins in biologically active states are not always present as oligomers such as dimer or trimer as in 2D or 3D crystals but as monomers in lipid bilayers. 

Zeth, K., Offermann, S., Essen, L.-O., and Oesterhelt, D. 2004. Iron-oxo clusters biomineralizing on protein surfaces structural analysis of Halobacterium salinarum DpsA in its low- and high-iron states. Proceedings of the National Academy of Sciences of the USA 101 13780-13785. 

Halobacterium salinarum Easy Low/easy Low Short/easy High Low... 

Sulfoglycodialkylglycerolipids from the halobacteiia, (a) Natralba asiatica, and (b) Halobacterium salinarum and Hb. saccharovorum. ff=SO r... 

In the present study, a FLIM measurement system was constructed and applied to Halobacterium salinarum (Hb. salinarum) loaded with 2, 7 -bis-(carboxyethyl)-5(6)-carboxyfluorescein (BCECF) to obtain information on the intracellular environment as well as the intracellular pH in each ofthe cells [9-12]. Hb. salinarum belongs to the family of extreme halophilic archaebacteria, and considerable attention has been paid to this bacterium in relation to proton transport, phototaxis or the adaptation of an organism to extreme environments [13-15]. Intracellular pH is an essential parameter for Hb. salinarum in the regulation of intracellular processes [14, 16, 17], and fluorescence intensity ratio methods have been used to measure the intracellular pH [18,19]. The... 

Koch, M.K. and Oesterhelt, D. (2005) MpcT is the transducer for membrane potential changes in Halobacterium salinarum. Mol. Microbiol., 55,... 

The mechanism of photosynthesis in chlorophyll is somewhat complex and is not as well known as the one that occurs via another chromophore (or pigment), a carotenoid, also shown in Figure 6.6. It requires a smaller number of steps and is simpler. It is also encountered in simpler and much easier to handle species, the purple membranes of special archaebacte-ria Halobacterium salinarum, which are found in great quantities in salt-saturated waters. 

Bacteriorhodopsin is the sole membrane protein of seven a-helical transmembrane chains present in the purple membrane of Halobacterium salinarum. This is active as a light-driven proton pump through the photoisomerization of retinal (Fig. 2) from the aW-trans, 15-anti to the 13-cis, 15-anti form covalently linked to Lys216 (helix G) of a single-chain polypeptide of 248 amino acid... 

Bacteriorhodopsin is a light-driven ion pump that is found in the purple membrane of the archaebacterium Halobacterium salinarum. Bacteriorhodopsin monomers consist of a bundle of seven transmembrane a-helices that are connected by short interhelical loops and enclose a molecule of retinal that is buried in the protein interior, approximately half way... 

In the following sections, the methods for phototaxis measurements in liquid cultures of Halobacterium salinarum, Rhodo-bacter sphaeroides, and Halorhodospim hedophila will be described in detail. 

For photo taxis assays, the cells are grown to the late exponential phase, diluted 100-fold in fresh medium, and grown for 2 h for use in motility measurements. The phototaxis response that will be observed depends critically on the strain of Halobacterium salinarum that is used see Note 1). 

Cercignani, G., Luda, S. and Petracchi, D. (1998). Photoresponses of Halobacterium salinarum to repetitive pulse stimuli. Biophys. J. 75, 1466-1472. 

Storch, K.-F., Rudolph, J. and Oesterhelt, D. (1999). Gar a cytoplasmic sensor responsible for arginine chemotaxis in the archaeon Halobacterium salinarum. EMBO ]. 18, 1146-1158. 

Yu, H.S. and Alam, M. (1997). An agarose-in-plug bridge method to study chemotaxis in the Archaeon Halobacterium salinarum. FEMS Microbiol. Lett. 156, 265-269. 

---