Interaction between the α-barrel tip of Vibrio vulnificus TolC homologs and AcrA implies the adapter bridging model.
The AcrAB-TolC multidrug efflux pump confers resistance to Escherichia coli against many antibiotics and toxic compounds. The TolC protein is an outer membrane factor that participates in the formation of type I secretion systems. The genome of Vibrio vulnificus encodes two proteins homologous to the E. coli TolC, designated TolCV1 and TolCV2. Here, we show that both TolCV1 and TolCV2 partially complement the E. coli TolC function and physically interact with the membrane fusion protein AcrA, a component of the E. coli AcrAB-TolC efflux pump. Using site-directed mutational analyses and an in vivo cross-linking assay, we demonstrated that the α-barrel tip region of TolC homologs plays a critical role in the formation of functional AcrAB-TolC efflux pumps. Our findings suggest the adapter bridging model as a general assembly mechanism for tripartite drug efflux pumps in Gram-negative bacteria.
Department of Life Science, Chung-Ang University, Seoul, 156-756, Republic of Korea.
Seunghwa
S
Lee
Saemee
S
Song
Minho
M
Lee
Soonhye
S
Hwang
Ji-Sun
JS
Kim
Nam-Chul
NC
Ha
Kangseok
K
Lee
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D016415:Sequence Alignment; D014357:Trypsin; D041261:Vibrio vulnificus / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D014357:Trypsin