Premium
Structure of Spa15, a type III secretion chaperone from Shigella flexneri with broad specificity
Author(s) -
van Eerde André,
Hamiaux Cyril,
Pérez Javier,
Parsot Claude,
Dijkstra Bauke W
Publication year - 2004
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/sj.embor.7400144
Subject(s) - effector , chaperone (clinical) , virulence , secretion , shigella flexneri , biology , type three secretion system , microbiology and biotechnology , shigella , pathogen , genetics , escherichia coli , biochemistry , gene , medicine , pathology
Type III secretion (TTS) systems are used by many Gram‐negative pathogens to inject virulence proteins into the cells of their hosts. Several of these virulence effectors require TTS chaperones that maintain them in a secretion‐competent state. Whereas most chaperones bind only one effector, Spa15 from the human pathogen Shigella flexneri and homologous chaperones bind several seemingly unrelated effectors, and were proposed to form a special subgroup. Its 1.8 Å crystal structure confirms this specific classification, showing that Spa15 has the same fold as other TTS effector chaperones, but forms a different dimer. The presence of hydrophobic sites on the Spa15 surface suggests that the different Spa15 effectors all possess similar structural elements that can bind these sites. Furthermore, the Spa15 structure reveals larger structural differences between class I chaperones than previously anticipated, which does not support the hypothesis that chaperone–effector complexes are structurally conserved and function as three‐dimensional secretion signals.