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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. The T4P machinery spans ~70 nm, significantly longer than that of mesophilic bacteria due to crossing the organism’s characteristically wide periplasm. The outer membrane secretin PilQ forms an extended secretion channel nearly twice as long as that in Pseudomonas aeruginosa and interacts with the T. thermophilus specific PilW, as well as conserved inner membrane components PilM, PilN, and PilO. T4P dynamics are powered by PilF and PilT ATPases, with PilT1 acting as the primary retraction ATPase. During transformation, DNA is thought to be pulled into the periplasm by T4P and then translocated into the cytoplasm via ComEA and ComEC. The pilus filament is mainly composed of major pilin PilA4, which polymerizes following N-terminal cleavage by PilD. 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. PilA5 forms a distinct narrow pilus involved in motility but not transformation. These features have been characterized mainly in strain HB27, and their conservation in other strains like HB8 remains unclear.


References

  • Uemura NA, Nakane D, (2025) Type IV pili in thermophilic bacteria: mechanisms and ecological implications. Biomolecules, 15, 459.
  • Yaman D, 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.
  • 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, 6330.
  • Salleh MZ, Karuppiah V, Snee M, Thistlethwaite A, Levy CW, Knight D, Derrick JP, (2019) Structure and properties of a natural competence-associated pilin suggest a unique pilus tip-associated DNA receptor. mBio, 10, e00614-19.
  • 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.
  • Salzer R, Kern T, 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.
  • 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.
  • 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, PilT1, and PilT2. Appl. Environ. Microbiol., 80, 644-652.
  • Lapointe CF, Taylor RK, (2000) The type 4 prepilin peptidases comprise a novel family of aspartic acid proteases. J. Biol. Chem., 275, 1502-1510.