Abstract
The SasG surface protein of Staphylococcus aureus has been shown to promote the formation of biofilm. SasG comprises an N-terminal A domain and repeated B domains. Here we demonstrate that SasG is involved in the accumulation phase of biofilm, a process that requires a physiological concentration of Zn2+. The B domains, but not the A domain, are required. Purified recombinant B domain protein can form dimers in vitro in a Zn2+-dependent fashion. Furthermore, the protein can bind to cells that have B domains anchored to their surface and block biofilm formation. The full-length SasG protein exposed on the cell surface is processed within the B domains to a limited degree, resulting in cleaved proteins of various lengths being released into the supernatant. Some of the released molecules associate with the surface-exposed B domains that remain attached to the cell. Studies using inhibitors and mutants failed to identify any protease that could cause the observed cleavage within the B domains. Extensively purified recombinant B domain protein is very labile, and we propose that cleavage occurs spontaneously at labile peptide bonds and that this is necessary for biofilm formation.
| Original language | English |
|---|---|
| Pages (from-to) | 5663-5673 |
| Number of pages | 11 |
| Journal | Journal of Bacteriology |
| Volume | 192 |
| Issue number | 21 |
| DOIs | |
| Publication status | Published - Nov 2010 |
Keywords
- POLYSACCHARIDE INTERCELLULAR ADHESIN
- FIBRONECTIN-BINDING PROTEINS
- MOLECULAR CHARACTERIZATION
- ANTIBIOTIC-RESISTANCE
- CLUMPING FACTOR
- EPIDERMIDIS
- FIBRINOGEN
- ADHERENCE
- VIRULENCE
- AUTOLYSIN