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ThermusQ> Pathway> PWBG0001

Description

Thermus thermophilus employs type IV pili (T4P) for diverse functions, including attachment, biofilm formation, DNA uptake, twitching motility, and phage infection [1]. The T4P machinery spans ~70 nm, significantly longer than that of mesophilic bacteria due to crossing the organism's characteristically wide periplasm [2]. The outer membrane secretin PilQ forms an extended secretion channel nearly twice as long as that in Pseudomonas aeruginosa [3] and interacts with the T. thermophilus specific PilW, as well as conserved inner membrane components PilM, PilN, and PilO [4].
T4P dynamics are powered by PilF and PilT ATPases, with PilT1 acting as the primary retraction ATPase [5]. During transformation, DNA is thought to be pulled into the periplasm by T4P and then translocated into the cytoplasm via ComEA and ComEC [6]. The pilus filament is mainly composed of major pilin PilA4, which polymerizes following N-terminal cleavage by PilD [7]. The genome encodes several pilA paralogs, including PilA1 and PilA2, which are implicated in DNA binding. PilA2 likely interacts with ComZ, a T. thermophilus specific protein, to mediate DNA uptake [8]. PilA5 forms a distinct narrow pilus involved in motility but not transformation [9]. These features have been characterized mainly in strain HB27, and their conservation in other strains like HB8 remains unclear.


References

  • Uemura D, Nakane D, (2025) Type IV pili in thermophilic bacteria: mechanisms and ecological implications. Biomolecules, 15, 459.
  • Gold VAM, Salzer R, Averhoff B, Kühlbrandt W, (2015) Structure of a type IV pilus machinery in the open and closed state. eLife, 4, e07380.
  • D'Imprima E, Salzer R, Bhaskara RM, Sánchez R, Rose I, Kirchner L, Hummer G, Kühlbrandt W, Vonck J, Averhoff B, (2017) Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus. eLife, 6, e30483.
  • Burkhardt J, Vonck J, Langer JD, Salzer R, Averhoff B, (2021) Functional dissection of structural regions of the Thermus thermophilus competence protein PilW: Implication in secretin complex stability, natural transformation and pilus functions. Biochim Biophys Acta Biomembr, 1863, 183666.
  • Salzer R, Kern T, Joos F, Averhoff B, (2014) Type IV pilus biogenesis, twitching motility, and DNA uptake in Thermus thermophilus: discrete roles of antagonistic ATPases PilF, PilT1, and PilT2. Appl Environ Microbiol, 80, 644–652.
  • Salzer R, Joos F, Averhoff B, (2016) The Thermus thermophilus comEA/comEC operon is associated with DNA binding and regulation of the DNA translocator and type IV pili. Environ Microbiol, 18, 65–74.
  • LaPointe CF, Taylor RK, (2000) The type 4 prepilin peptidases comprise a novel family of aspartic acid proteases. J Biol Chem, 275, 1502–1510.
  • Salzer R, D'Imprima E, Gold VAM, Rose I, Drechsler M, Vonck J, Averhoff B, (2019) Structure and properties of a natural competence-associated pilin suggest a unique pilus tip-associated DNA receptor. mBio, 10, e00614-19.
  • Neuhaus A, Selvaraj M, Salzer R, Langer JD, Kruse K, Kirchner L, Sanders K, Daum B, Averhoff B, Gold VAM, (2020) Cryo-electron microscopy reveals two distinct type IV pili assembled by the same bacterium. Nat Commun, 11, 2231.