TatB and TatC form a functional and structural unit of the twin-arginine translocase from Escherichia coli.
In Escherichia coli, a subset of periplasmic proteins is exported via the twin-arginine translocation (Tat) pathway. In the present study, we have purified the Tat complex from E. coli, and we show that it contains only TatA, TatB, and TatC. Within the purified complex, TatB and TatC are present in a strict 1:1 ratio, suggesting a functional association. This has been confirmed by expression of a translational fusion between TatB and TatC. This Tat(BC) chimera supports efficient Tat-dependent export, indicating that TatB and TatC act as a unit in both structural and functional terms. The purified Tat complex contains varying levels of TatA, suggesting a gradual loss during isolation and a looser association. The molecular mass of the complex is approximately 600 kDa, demonstrating the presence of multiple copies of TatA, B, and C. Co-immunoprecipitation experiments show that TatC is required for the interaction of TatA with TatB, suggesting that TatA may interact with the complex via binding to TatC.
Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom.
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A
Bolhuis
J E
JE
Mathers
J D
JD
Thomas
C M
CM
Barrett
C
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Robinson
D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017931:DNA Primers; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D008970:Molecular Weight; D009876:Operon; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D002352:Carrier Proteins; D017931:DNA Primers; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D011993:Recombinant Fusion Proteins; C408585:twin-arginine translocase complex, E coli