Haemophilus influenzae surface fibril (Hsf) is a unique twisted hairpin-like trimeric autotransporter.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift


The Haemophilus surface fibril (Hsf) is an extraordinary large (2413 amino acids) trimeric autotransporter, present in all encapsulated Haemophilus influenzae. It contributes to virulence by directly functioning as an adhesin. Furthermore, Hsf recruits the host factor vitronectin thereby inhibiting the host innate immune response resulting in enhanced survival in serum. Here we observed by electron microscopy that Hsf appears as an 100nm long fibril at the bacterial surface albeit the length is approximately 200nm according to a bioinformatics based model. To unveil this discrepancy, we denaturated Hsf at the surface of Hib by using guanidine hydrochloride (GuHCl). Partial denaturation induced in the presence of GuHCl unfolded the Hsf molecules, and resulted in an increased length of fibres in comparison to the native trimeric form. Importantly, our findings were also verified by E. coli expressing Hsf at its surface. In addition, a set of Hsf-specific peptide antibodies also indicated that the N-terminal of Hsf is located near the C-terminal at the base of the fibril. Taken together, our results demonstrated that Hsf is not a straight molecule but is folded and doubled over. This is the first report that provides the unique structural features of the trimeric autotransporter Hsf.


  • Birendra Singh
  • Al-Jubair Tamim
  • Matthias Mörgelin
  • Anders Sundin
  • Sara Linse
  • Ulf J Nilsson
  • Kristian Riesbeck
Enheter & grupper

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Mikrobiologi inom det medicinska området
Sidor (från-till)27-37
TidskriftInternational Journal of Medical Microbiology
StatusPublished - 2015
Peer review utfördJa


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Relaterad forskningsoutput

Tamim, A-J., 2016, Lund: Lund University, Faculty of Medicine. 74 s.

Forskningsoutput: AvhandlingDoktorsavhandling (sammanläggning)

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