Protein A Is Released into the Staphylococcus aureus Culture Supernatant with an Unprocessed Sorting Signal.
Item Type:Journal Article
Citation:Joan Geoghegan, Dara O'Halloran, Kieran Wynne, 'Protein A Is Released into the Staphylococcus aureus Culture Supernatant with an Unprocessed Sorting Signal.', 2015, Infection and immunity;, 83;, 4;
Infect. Immun.-2015-O'Halloran-IAI.03122-14.pdf (Accepted for publication (author's copy) - Peer Reviewed) 3.884Mb
The immunoglobulin binding protein A (SpA) of Staphylococcus aureus is synthesized as a precursor with a C-terminal sorting signal. The sortase A enzyme mediates covalent attachment to peptidoglycan so that SpA is displayed on the surface of the bacterium. Protein A is also found in the extracellular medium but the processes involved in its release are not fully understood. Here we show that a portion of SpA is released into the supernatant with an intact sorting signal indicating that it has not been processed by sortase A. Release of SpA was reduced when the native sorting signal of SpA was replaced with the corresponding region of another sortase-anchored protein (SdrE). Similarly, a reporter protein fused to the sorting signal of SpA was released to a greater extent than the same polypeptide fused to the SdrE sorting signal. Released SpA protected bacteria from killing in human blood indicating that it contributes to immune evasion.
Type of material:Journal Article
Series/Report no:Infection and immunity;
Availability:Full text available