@article{BenzJonesYounasetal.2015, author = {Benz, Roland and Jones, Michael D. and Younas, Farhan and Maier, Elke and Modi, Niraj and Mentele, Reinhard and Lottspeich, Friedrich and Kleinekath{\"o}fer, Ulrich and Smit, John}, title = {OmpW of Caulobacter crescentus functions as an outer membrane channel for cations}, series = {PLoS ONE}, volume = {10}, journal = {PLoS ONE}, number = {11}, doi = {10.1371/journal.pone.0143557}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-145114}, pages = {e0143557}, year = {2015}, abstract = {Caulobacter crescentus is an oligotrophic bacterium that lives in dilute organic environments such as soil and freshwater. This bacterium represents an interesting model for cellular differentiation and regulation because daughter cells after division have different forms: one is motile while the other is non-motile and can adhere to surfaces. Interestingly, the known genome of C. crescentus does not contain genes predicted to code for outer membrane porins of the OmpF/C general diffusion type present in enteric bacteria or those coding for specific porins selective for classes of substrates. Instead, genes coding for 67 TonB-dependent outer membrane receptors have been identified, suggesting that active transport of specific nutrients may be the norm. Here, we report that high channel-forming activity was observed with crude outer membrane extracts of C. crescentus in lipid bilayer experiments, indicating that the outer membrane of C. crescentus contained an ion-permeable channel with a single-channel conductance of about 120 pS in 1M KCl. The channel-forming protein with an apparent molecular mass of about 20 kDa was purified to homogeneity. Partial protein sequencing of the protein indicated it was a member of the OmpW family of outer membrane proteins from Gram-negative bacteria. This channel was not observed in reconstitution experiments with crude outer membrane extracts of an OmpW deficient C. crescentus mutant. Biophysical analysis of the C. crescentus OmpW suggested that it has features that are special for general diffusion porins of Gram-negative outer membranes because it was not a wide aqueous channel. Furthermore, OmpW of C. crescentus seems to be different to known OmpW porins and has a preference for ions, in particular cations. A putative model for OmpW of C. crescentus was built on the basis of the known 3D-structures of OmpW of Escherichia coli and OprG of Pseudomonas aeruginosa using homology modeling. A comparison of the two known structures with the model of OmpW of C. crescentus suggested that it has a more hydrophilic interior and possibly a larger diameter.}, language = {en} } @article{GoetzKoesterWinkleretal.1994, author = {G{\"o}tz, Rudolf and K{\"o}ster, Reinhard and Winkler, Christoph and Raulf, Friedrich and Lottspeich, Friedrich and Schartl, Manfred and Thoenen, Hans}, title = {Neurotrophin-6 is a new member of the nerve growth factor family}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61544}, year = {1994}, abstract = {DURING vertebrale development, many neurons depend for survival and differentiation on their target cells\(^{1-3}\). The best documented mediator of such a retrograde trophic action is the neurotrophin nerve growth factor (NGF)\(^1\). NGF and the other known members of tbe neurotrophin family, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT -3) and neurotrophin-4/5 (NT -4/5) are conserved as distinct genes over large evolutionary distances\(^{4 -6}\). Here we report the cloning of neurotrophin-6 (NT -6), a new member of this family from the teleost fish Xiphophorus. NT -6 distinguishes itself from the other known neurotrophins in that it is not found as a soluble protein in the medium of producing cells. The addition of heparin (but not chondroitin) effects the release of NT -6 from cell surface and extracellular matrix molecules. Recombinant purified NT -6 has a spectrum of actions similar to NGF on chick sympathetic and sensory neurons, albeit with a lower potency. NT -6 is expressed in tbe embryonie valvulla cerebelli; expression persists in some adult tissues. The interaction of NT-6 with heparin-binding molecuJes may modulate its action in the nervous system .}, subject = {Physiologische Chemie}, language = {en} } @article{KreftFunkeHaasetal.1989, author = {Kreft, J{\"u}rgen and Funke, Dorothee and Haas, Albert and Lottspeich, Friedrich and Goebel, Werner}, title = {Production, purification and characterization of hemolysins from Listeria ivanovii and Listeria monocytogenes Sv4b.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60545}, year = {1989}, abstract = {In culture supematants of both Listeria ivanovii and Listeria monocytogenes Sv4b, for the first time a hemolysin of molecular weight 58 kDa was identified, which had all the characteristics of an SH-activated cytolysin, and which was therefore identified as Iisteriolysin 0 (LLO). In the case of L. ivanovii a second major supematant protein of molecular weight 24 kDa co-purified with LLO. However, the function of this protein has to be determined. In culture supematants of L. ivanovii a sphingomyelinase and a Iecithinase activity could be detected, both enzymatic activities together contributing to the pronounced hemolysis caused by L. ivanovii. The N-tenninal amino acid sequences of LLO and the 24 kDa from L. ivanovii are shown.}, subject = {Biologie}, language = {en} }