The structural organization of the N-terminus domain of SopB, a virulence factor of Salmonella, depends on the nature of its protein partners.
The TTSS is used by Salmonella and many bacterial pathogens to inject virulence factors directly into the cytoplasm of target eukaryotic cells. Once translocated these so-called effector proteins hijack a vast array of crucial cellular functions to the benefit of the bacteria. In the bacterial cytoplasm, some effectors are stabilized and maintained in a secretion competent state by interaction with specific type III chaperones. In this work we studied the conformation of the Chaperone Binding Domain of the effector named Salmonella Outer protein B (SopB) alone and in complex with its cognate chaperone SigE by a combination of biochemical, biophysical and structural approaches. Our results show that the N-terminus part of SopB is mainly composed by α-helices and unfolded regions whose organization/stabilization depends on their interaction with the different partners. This suggests that the partially unfolded state of this N-terminal region, which confers the adaptability of the effector to bind very different partners during the infection cycle, allows the bacteria to modulate numerous host cells functions limiting the number of translocated effectors.
INRA Biopolymères, Interactions et Assemblages, Rue de la Geraudière, 44316 Nantes, France; Synchrotron SOLEIL, L'orme des Merisiers, Saint Aubin, BP 48, 91192 Gif sur Yvette Cedex, France. Electronic address: pierre.roblin@synchrotron-soleil.fr.
Pierre
P
Roblin
Pierre
P
Lebrun
Prakash
P
Rucktooa
Frederique
F
Dewitte
Zoe
Z
Lens
Véronique
V
Receveur-Brechot
Vincent
V
Raussens
Vincent
V
Villeret
Coralie
C
Bompard
D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012486:Salmonella typhimurium / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D018832:Molecular Chaperones; D012808:Sigma Factor; C111259:sigE protein, Bacteria; C489224:SopB protein, Salmonella
Bacterial virulence; CBD; CD; Chaperone binding domain; DSP; Intrinsically disordered protein; R(g); R(h); SAXS; Salmonella outer protein B; Small angle X-ray scattering; SopB; TTSS; Type three secretion system; chaperone binding domain; circular dichroism; dithio-bis-(succinimidylpropionate); hydrodynamic radius; radius of gyration; small angle X-ray scattering; type three secretion system