Abstract
The fimbriae-associated protein 1 (Fap1) is a major adhesin of Streptococcus parasanguinis, a primary colonizer of the oral cavity that plays an important role in the formation of dental plaque. Fap1 is an extracellular adhesive surface fibre belonging to the serine-rich repeat protein (SRRP) family, which plays a central role in the pathogenesis of streptococci and staphylococci. The N-terminal adhesive region of Fap1 (Fap1-NR) is composed of two domains (Fap1-NR α and Fap1-NR β) and is projected away from the bacterial surface via the extensive serine-rich repeat region, for adhesion to the salivary pellicle. The adhesive properties of Fap1 are modulated through a pH switch in which a reduction in pH results in a rearrangement between the Fap1-NR α and Fap1-NR β domains, which assists in the survival of S. parasanguinis in acidic environments. We have solved the structure of Fap1-NR α at pH 5.0 at 3.0Ǻ resolution and reveal how subtle rearrangements of the 3-helix bundle combined with a change in electrostatic potential mediates 'opening' and activation of the adhesive region. Further, we show that pH-dependent changes are critical for biofilm formation and present an atomic model for the inter-Fap1-NR interactions which have been assigned an important role in the biofilm formation.
Original language | English |
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Pages (from-to) | 421-426 |
Number of pages | 6 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 417 |
Issue number | 1 |
DOIs | |
State | Published - 06 01 2012 |
Keywords
- Adhesion
- Biofilm
- Dental plaque
- Fimbriae
- Serine-rich repeat
- Streptococci