@article{mbs:/content/journal/micro/10.1099/mic.0.26997-0, author = "Zurawski, Daniel V. and Stein, Murry A.", title = "The SPI2-encoded SseA chaperone has discrete domains required for SseB stabilization and export, and binds within the C-terminus of SseB and SseD", journal= "Microbiology", year = "2004", volume = "150", number = "7", pages = "2055-2068", doi = "https://doi.org/10.1099/mic.0.26997-0", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.26997-0", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "EPEC, enteropathogenic E. coli", keywords = "MCS, multiple cloning site", keywords = "GST, glutathione S-transferase", keywords = "LEE, locus for enterocyte effacement", keywords = "TTS, type III secretion", keywords = "SPI2, Salmonella pathogenicity island 2", abstract = "SseA, a key Salmonella virulence determinant, is a small, basic pI protein encoded within the Salmonella pathogenicity island 2 and serves as a type III secretion system chaperone for SseB and SseD. Both SseA partners are subunits of the surface-localized translocon module that delivers effectors into the host cell; SseB is predicted to compose the translocon sheath and SseD is a putative translocon pore subunit. In this study, SseA molecular interactions with its partners were characterized further. Yeast two-hybrid screens indicate that SseA binding requires a C-terminal domain within both partners. An additional central domain within SseD was found to influence binding. The SseA-binding region within SseB was found to encompass a predicted amphipathic helix of a type participating in coiled-coil interactions that are implicated in the assembly of translocon sheaths. Deletions that impinge upon this putative coiled-coiled domain prevent SseA binding, suggesting that SseA occupies a portion of the coiled-coil. SseA occupancy of this motif is envisioned to be sufficient to prevent premature SseB self-association inside bacteria. Domain mapping on the chaperone was also performed. A deletion of the SseA N-terminus, or site-directed mutations within this region, allowed stabilization of SseB, but its export was disrupted. Therefore, the N-terminus of SseA provides a function that is essential for SseB export, but dispensable for partner binding and stabilization.", }