Shuffling genes around in hotenvironments
The DNA translocator of Thermus thermophilus as model system for macromolecuar transport machineries
Natural genetic transformation, also referred to as “natural competence”, permits the exchange of free DNA among organisms of different domains and, therefore, is suggested to be a driving force for bacterial adaptation and genome evolution. Both, induction of competence and the physiology of natural transformation have been intensively studied in mesophilic bacteria and there is a considerable body of literature. In contrast, much less is known about the mechanism of DNA transport and the structure and function of the DNA transport machineries. Moreover, information with respect to natural transformation systems in thermophilic bacteria is even more scarce.The latter is of prime interest since thermophilic bacteria clearly stand out in terms of interdomain DNA transfer and massive interdomain gene transfer between hyperthermophilic archaea and bacteria is suggested to play a major role in adaptation to hot environments. To get insights into the transformation machinery of extremely thermophilic bacteria we chose Thermus thermophilus HB27. This strain exhibits highest natural transformation frequencies known to date. We performed broad physiological, molecular, biochemical, immunological and electron microscopical studiesandidentified genes, proteins and macromolecular complexes of the DNA translocator. We unravelled the structure and function and the interplay of subunits of the DNA translocator and the data have culminated in a model of a highly complex DNA translocator spanning the whole cell periphery of T. thermophilus. Currently we focuss on the elucidation of the atomic structure and the molecular mechanism of DNA uptake and analyze the in vivo dynamics and regulation of the DNA transporter system. These questions are addressed by modern state of the art techniques such as cryo electronmicroscopy, tomography, crystallisation and in vivo labeling techniques.
Model of the DNA translocator of Thermus thermophilus.
Salzer, R., Herzberg, M, Nies, D.H., Joos, F., Rathmann, B., Thielmann, Y., Averhoff, B. (2014) Zinc and ATP binding of the hexameric AAA-ATPase PilF from T. thermophilus: Role in complex stability, piliation, adhesion, twitching motility and natural transformation.J. Biol. Chem., in press.
Salzer, R., Kern, T., Joos, F., Averhoff, B. (2014) Environmental factors affecting the expression of type IV pilus genes as well as piliation of Thermus thermophilus. FEMS Microbiol. Lett. 357 : 56-62.
Salzer, R., Joos, F., Averhoff, B. (2014) Type IV pilus biogenesis, twitching motility, and DNA uptake in Thermus thermophilus: discrete roles of antagonistic ATPases PilF, Pil1, and Pil2. Appl. Environ. Microbiol. 80 : 644-652.
Salzer, R., Herzberg, M., Nies, D.H., Biukovic, G., Grüber, G., Müller, V., Averhoff, B. (2013) The DNA uptake ATPase PilF ofThermus thermophilus: a reexamination of the zinc content. Extremophiles 17 : 697-698.
Nordgard, L., Brusetti, L., Raddadi, N., Traavik, T., Averhoff, B., Nielsen K.M. (2012) An investigation of horizontal transfer of feed introduced DNA to the aerobic microbiota of the gastrointestinal tracts of rats. BMC Res. Notes 5 : 170.
Burkhardt, J., Vonck, J., Langer, J.D., Salzer, R., Averhoff, B. (2012) An unusual N-terminal ααβαββα fold of PilQ from T. thermophilus mediates ring formation and is essential for piliation. J. Biol. Chem. 287 : 8484-8494.
Burkhardt, J., Vonck, J., Averhoff, B. (2011) Structure and function of PilQ, a secretin of the DNA transporter from the thermophilic bacterium Thermus thermophilus HB27. J. Biol. Chem. 286 : 9977-9984.
Averhoff, B., Müller, V. (2010) Exploring research frontiers in microbiology: recent advances in halophilic and thermophilic extremophiles. Res. Microbiol. 161 : 506-514.
Schwarzenlander, C., Haase, W., Averhoff, B. (2009) The role of single subunits of the DNA transport machinery of Thermus thermophilus HB27 in DNA binding and transport. Environ. Microbiol. 4 : 801-808.
Averhoff, B.(2009) Shuffling genes around in hot environments: the unique DNA transporter of Thermus thermophilus. FEMS Microbiol Rev. 33 : 6611-6626.
Schwarzenlander, C., Averhoff, B. (2006) Characterization of DNA transport in the thermophilic bacterium Thermus thermophilus HB27. FEBS J., 273 : 4210-4218.
Averhoff, B.(2006) Genetic systems for Thermus. In: Extremophiles (Methods in Microbiology), Rainey F & Oren A (eds), Vol. 35, pp 279-308, Oxford: Oxford Academic Press.
Gohl, O., Friedrich, A., Hoppert, M., Averhoff, B. (2006) The thin pili of Acinetobacter sp. strain BD413 mediate adhesion to biotic and abiotic surfaces. Appl. Environ. Microbiol. 72 : 1394-1401.
Rumszauer, J., Schwarzenlander, C., Averhoff, B. (2006) Identification, subcellular localization and functional interactions of PilMNOWQ and PilA4 involved in transformation competency and pilus biogenesis in the thermophilic bacterium Thermus thermophilus HB27. FEBS J., 273 : 3261-3272.
Averhoff, B.(2004) DNA transport and natural transformation in mesophilic and thermophilic bacteria. J. Bioenerg. Biomembr. 36 : 25-33.
Averhoff, B., Friedrich, A. (2003) Type IV pili-related natural transformation systems: DNA transport in mesophilic and thermophilic bacteria. Arch. Microbiol. 18 : 385-393.
Averhoff, B.(2003) Horizontaler Gentransfer in extrem thermophilen Mikroorganismen. Biospektrum 1 : 36-37.
Friedrich, A., Rumszauer, J., Henne, A., Averhoff, B. (2003) Pilin-like proteins in the extremely thermophilic Thermus thermophilus HB27: implication in competence for natural transformation and links to type IV pili biogenesis. Appl. Environ. Microbiol. 69 : 3695-3700.
Friedrich, A., Prust, C., Hartsch, T., Henne, A., Averhoff, B. (2002) Molecular analyses of the natural transformation machinery and identification of pilus structures in the extremely thermophilic bacterium Thermus thermophilus strain HB27. Appl. Environ. Microbiol. 68 : 745-755.