YknWXYZ is an unusual four-component transporter with a role in protection against sporulation-delaying-protein-induced killing of Bacillus subtilis.
YknXYZ is the ATP-binding cassette export complex from Bacillus subtilis, where YknX is a membrane fusion protein, YknY is an ATPase, and YknZ is a permease. The yknXYZ genes are arranged into an operon that also includes yknW, encoding a membrane protein with four putative transmembrane segments. Previous studies suggested that the yknWXYZ operon belongs to the σ(w) regulon and protects cells from the endogenous toxin SDP (sporulation-delaying protein) encoded by sdpC. In this study, we investigated the composition and function of YknW and YknXYZ. We report that the yknWXYZ operon is constitutively expressed in growing B. subtilis cells independently from sdpC. Chemical cross-linking in vivo and copurification approaches established that YknX interacts with YknYZ, whereas YknW binds YknXYZ, indicating that all four proteins form a complex in vivo. The complex assembly is modulated by YknW but proceeds in the absence of SdpC. When overproduced alone, YknW provides partial protection against SDP toxin, but all four Ykn proteins are required for full protection against both endogenous and exogenous SDP. We conclude that YknWXYZ is an unusual four-component transporter with a role in the starvation-induced killing of B. subtilis cells.
Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Life Science Research Center, Norman, Oklahoma, USA.
Yoichi
Y
Yamada
Elena B
EB
Tikhonova
Helen I
HI
Zgurskaya
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D050296:Microbial Viability; D009876:Operon; D011485:Protein Binding; D025941:Protein Interaction Mapping; D013171:Spores, Bacterial / Q000254:growth & development*
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D001427:Bacterial Toxins