A type VII-secreted lipase toxin with reverse domain arrangement

Autor: Stephen R. Garrett, Nicole Mietrach, Justin Deme, Alina Bitzer, Yaping Yang, Fatima R. Ulhuq, Dorothee Kretschmer, Simon Heilbronner, Terry K. Smith, Susan M. Lea, Tracy Palmer
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Nature Communications, Vol 14, Iss 1, Pp 1-16 (2023)
Druh dokumentu: article
ISSN: 2041-1723
DOI: 10.1038/s41467-023-44221-y
Popis: Abstract The type VII protein secretion system (T7SS) is found in many Gram-positive bacteria and in pathogenic mycobacteria. All T7SS substrate proteins described to date share a common helical domain architecture at the N-terminus that typically interacts with other helical partner proteins, forming a composite signal sequence for targeting to the T7SS. The C-terminal domains are functionally diverse and in Gram-positive bacteria such as Staphylococcus aureus often specify toxic anti-bacterial activity. Here we describe the first example of a class of T7 substrate, TslA, that has a reverse domain organisation. TslA is widely found across Bacillota including Staphylococcus, Enterococcus and Listeria. We show that the S. aureus TslA N-terminal domain is a phospholipase A with anti-staphylococcal activity that is neutralised by the immunity lipoprotein TilA. Two small helical partner proteins, TlaA1 and TlaA2 are essential for T7-dependent secretion of TslA and at least one of these interacts with the TslA C-terminal domain to form a helical stack. Cryo-EM analysis of purified TslA complexes indicate that they share structural similarity with canonical T7 substrates. Our findings suggest that the T7SS has the capacity to recognise a secretion signal present at either end of a substrate.
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