Recombinant Staphylococcus aureus UPF0738 protein SAS0874 (SAS0874)
Description
General Information
The Staphylococcus aureus surface protein SasC, also known as UPF0738 protein SAS0874, is a protein factor involved in cell aggregation and biofilm formation . Biofilms are three-dimensional structures made of bacteria and host material, and their formation is a critical factor in implant-associated infections . SasC does not mediate binding to fibrinogen, thrombospondin-1, von Willebrand factor, or platelets .
Gene and Protein Structure
The sasC gene consists of 6558 nucleotides and encodes a protein of 2186 amino acids with a predicted molecular mass of 237.9 kDa . The deduced SasC sequence contains a signal peptide in the first 37 amino acids that contains an YSIRK motif, which seems to play a role in signal peptide processing . The predicted sasC gene product is composed of 25.1% hydrophobic, 12.1% basic, and 13.2% acidic amino acids, and its theoretical pI value is 5.08 .
Homology
The deduced amino acid sequence of SasC of strain 4074 shares:
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97% identical amino acids with homologous proteins from strains S. aureus MW2 and MSSA476
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96% identical amino acids with strains USA300, COL, Newman, NCTC8325, and N315
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31% identical amino acids with Mrp and FmtB proteins from strain Col that have been implicated in methicillin-resistance
Role in Cell Aggregation and Biofilm Formation
S. carnosus expressing sasC formed cell aggregates indicative of intercellular adhesion, which were disintegrated by protease treatment . Upon plasmid-encoded expression of sasC, S. carnosus as well as S. aureus formed a more pronounced biofilm in microtiter plates as well as in glass tubes than the respective wild-type strains . The domain conferring cell aggregation and biofilm formation was localized to the N-terminal domain of SasC .
