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Research interests of the Group:
One of the main interests of our group is the analysis of polysaccharide and oligosaccharide breakdown and utilization by microorganisms adapted to extreme habitats. In particular, we are interested in cellulose, xylan and starch degrading enzyme systems from hyperthermophiles, i. e. organisms that grow optimally at 80°C or higher. These organisms represent very deep branches within the prokaryotic lineages of the phylogenetic tree of organisms. We are interested in the biochemical properties, the molecular structure and catalytic mechanism, the function(s) of non-catalytic domains, and the cellular localization of unusual glycosyl hydrolases and transferases from Thermotoga maritima, the model organism of hyperthermophilic bacteria. Other projects in the field of extremophilic microorganisms deal with the enzymology and molecular biology of thermoalkaliphiles and thermoacidophiles.
In the field of genome research, we have completed the genome sequence of the extreme thermoacidophilic archaeon Picrophilus torridus in collaboration with the Göttingen Genomics Laboratory. The objectives of this work are to better understand the evolutionary, metabolic and molecular mechanisms that allow this organism to thrive at up to 65°C at pH values close to pH 0. Also, in collaboration with PD Dr. R. Daniel we are interested in the characterization of genome (metagenome) structures of various microbial habitats. DNA libraries are constructed from microbial consortia and biofilms in order to explore the genetic diversity of the different environments. Also, classical activity-based screens are used for the isolation of novel enzymes useful for biotechnology (Dr. A. Angelov).
Together with Dr. A. Ehrenreich, a research project aimed at the clarification of selected pathways of carbon and energy metabolism of the acetic acid bacterium Gluconobacter oxydans has been initiated.
Another group of bacteria studied in the laboratory are the Gram-positive bacteria with a high G+C content. We employ molecular biological techniques to study and modify physiological traits of corynebacteria and micrococci.
Wolfgang Liebl is coordinator of a research network of collaborative projects funded by the Federal Ministry of Education and Research (BMBF), entitled "BiotechGenoMik - from Genomes to Functions to Products".
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Picrophilus torridus
Thermotoga maritima
Thermus thermophilus
Corynebacterium glutamicum
Gluconobacter oxydans
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Selected publications (W. Liebl):
Liebl, W., Winterhalter, C., Baumeister, W., Armbrecht, M., Valdez, M. (2007) Xylanase attachment to the cell wall of the hyperthermophilic bacterium Thermotoga maritima. J. Bacteriol. (Epub ahead of print)
Angelov, A., Liebl, W. (2006) Insights into extreme thermoacidophily based on genome analysis of Picrophilus torridus and other thermoacidophilic archaea. J. Biotechnol. 126:3-10.
Angelov, A., Putyrski, M., Liebl, W. (2006) Molecular and biochemical characterization of alpha-glucosidase and alpha-mannosidase and their clustered genes from the thermoacidophilic archaeon Picrophilus torridus. J. Bacteriol. 188(20):7123-7131.
Ballschmiter, M., Fütterer, O., Liebl, W. (2006) Identification and characterization of a novel intracellular alkaline alpha-amylase from the hyperthermophilic bacterium Thermotoga maritima MSB8. Appl. Environ. Microbiol. 72(3):2206-2211.
Dickmanns, A., Ballschmiter, M., Liebl, W., Ficner, R. (2006) Structure of the novel alpha-amylase AmyC from Thermotoga maritima. Acta Crystallogr. D. Biol. Crystallogr. 62(Pt 3):262-270.
Kleine, J., Liebl, W. (2006) Comparative characterization of deletion derivatives of the modular xylanase XynA of Thermotoga maritima. Extremophiles 10(5):373-381.
Angelov A, Fütterer O, Valerius O, Braus GH, Liebl W (2005) Properties of the recombinant glucose/galactose dehydrogenase from the extreme thermoacidophile, Picrophilus torridus. FEBS J (Eur J Biochem) 272:1054-1062
Ballschmiter M, Armbrecht M, Ivanova K, Liebl W (2005) AmyA, an alpha-amylase with beta-cyclodextrin-forming activity, and AmyB from the thermoalkaliphile Anaerobranca gottschalkii: two a-amylases adapted to their different cellular localization. Appl. Environ. Microbiol. 71: 3709-3715.
Liebl W (2005) Corynebacterium Taxonomy. In: Handbook of Corynebacterium glutamicum (L. Eggeling and M. Bott, ed.), CRC Press, pp. 9-34
Liebl W (2004) Genomics taken to the extreme. Nature Biotechnology 22: 524-525
Fütterer O, Angelov A, Liesegang H, Gottschalk G, Schleper C, Schepers B, Dock C, Antranikian G, Liebl W (2004) Genome sequence of Picrophilus torridus and its implications for life around pH 0. Proc Natl Acad Sci USA 101: 9091-9096
Bertoldo C, Armbrecht M, Becker F, Schäfer T, Antranikian G, Liebl W (2004) Cloning, sequencing and characterization of thermoalkalistable pullulanase type I from Anaerobranca gottschalkii. Appl. Environ. Microbiol. 70:3407-3416
Tzvetkov M, Klopprogge C, Zelder O, Liebl W (2003) Genetic dissection of trehalose biosynthesis in Corynebacterium glutamicum: inactivation of trehalose production leads to impaired growth and an altered cell wall lipid composition. Microbiology 149:1659-1673
Lodge JA, Maier T, Liebl W, Hoffmann V, Sträter N. (2003) Crystal structure of Thermotoga maritima alpha-glucosidase AglA defines a new clan of NAD+-dependent glycosidases. J. Biol. Chem. 278:19151-19158
Raasch C, Armbrecht M, Streit W, Höcker B, Sträter N, Liebl W (2002) Identification of residues important for NAD+-binding by the Thermotoga maritima alpha-glucosidase AglA, a member of glycoside hydrolase family 4. FEBS Lett. 517:267-271
Liebl W, Kloos WE, Ludwig W (2002) Plasmid-borne macrolide resistance in Micrococcus luteus. Microbiology 148:2479-2487
Sterner R, Liebl W (2001) Thermophilic adaptation of proteins. Crit. Rev. Biochem. Mol. Biol. 36:39-106
Entcheva P, Liebl W, Johann A, Hartsch T, Streit W (2001) Direct cloning from enrichment cultures, a reliable strategy for isolation of complete operons and genes from microbial consortia. Appl. Environ. Microbiol. 67:89-99
Roujeinikova A, Raasch C, Burke J, Baker PJ, Liebl W, Rice DW (2001) The crystal structure of Thermotoga maritima maltosyltransferase and its implications for the molecular basis of the novel transfer specificity. J. Mol. Biol. 312:119-131
Meissner K, Wassenberg D, Liebl W (2000) The ‘thermostabilising domain’ of the modular xylanase XynA of the hyperthermophilic bacterium Thermotoga maritima represents a novel type of binding domain with affinity for soluble xylan and mixed-linkage beta -1,3/beta -1,4-glucan. Mol. Microbiol, 36:898-912
Wassenberg D, Liebl W, Jaenicke R (2000) Maltose-binding protein from the hyperthermophilic bacterium Thermotoga maritima: Stability and binding properties. J. Mol. Biol., 295:279-288
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