Characterization of DNA transport in the thermophilic bacterium Thermus thermophilus HB27

Abstract

Horizontal gene transfer has been a major force for genome plasticity over evolutionary history, and is largely responsible for fitness‐enhancing traits, including antibiotic resistance and virulence factors. In particular, for adaptation of prokaryotes to extreme environments, lateral gene transfer seems to have played a crucial role. Recently, by performing a genome‐wide mutagenesis approach with Thermus thermophilus HB27, we identified the first genes in a thermophilic bacterium for the uptake of free DNA, a process called natural transformation. Here, we present the first data on the biochemistry and bioenergetics of the DNA transport process in this thermophile. We report that linear and circular plasmid DNA are equally well taken up with a high maximal velocity of 1.5 µg DNA·(mg protein)−1·min−1, demonstrating an extremely efficient binding and uptake rate of 40 kb·s−1·cell−1. Uncouplers and ATPase inhibitors immediately inhibited DNA uptake, providing clear evidence that DNA translocation in HB27 is an energy‐dependent process. DNA uptake studies with genomic DNA of Bacteria, Archaea and Eukarya revealed that Thermus thermophilus HB27 takes up DNA from members of all three domains of life. We propose that the extraordinary broad substrate specificity of the highly efficient Thermus thermophilus HB27 DNA uptake system may contribute significantly to thermoadaptation of Thermus thermophilus HB27 and to interdomain DNA transfer in hot environments.

Transferable Denitrification Capability of Thermus thermophilus

“…Natural competence, particularly in the HB27 strain, is highly efficient and apparently constitutive, allowing incorporation rates of 40 kbp/cell/s without much difference regarding its origin (34). This promiscuity has made this strain the ideal thermophilic laboratory model, allowing the development of a complete genetic toolbox to analyze the function of any given protein in vivo (28).…”

Zinc and ATP Binding of the Hexameric AAA-ATPase PilF from Thermus thermophilus

“…It catalyzes the first step in DNA recognition (9). Second, it has a pilus-like structure (PilA1-4) mediating the transport of DNA into a DNase-resistant state and is suggested to be a dynamic structure (10).…”

Partial and complete denitrification in Thermus thermophilus: lessons from genome drafts

“…Both strains are strict aerobes, despite the presence of some genes usually associated with anaerobic metabolism, which was revealed when their sequences were published [9]. Natural competence, in particular in the HB27 strain, is highly efficient and apparently constitutive, allowing incorporation rates of 40 kb per cell and secondly without much difference regarding its origin [10]. This promiscuity has made this strain an ideal laboratory model, allowing the development of a complete genetic toolbox, through which it is possible to analyse the actual function of a given protein in vivo [1].…”