Figure 6: Homo-oligomerization of TatC and its contacts to TatA are influenced by TatB.
From: Initial assembly steps of a translocase for folded proteins
(a) Membrane vesicles containing the indicated Bpa variants of TatC (Fig. 2a) were probed for inter-TatC crosslinks (blue stars). Shown are western blots decorated with anti-TatC antibodies (αTatC). TatB–TatC adducts (black dots) had been identified as such in Fig. 2a and TatA–TatC adducts (squares) are addressed in b and c. (b,c) As in a, except that membrane vesicles used were devoid of TatB. Ultraviolet light-dependent adducts to the indicated Bpa variants of TatC were probed by antibodies against TatC (αTatC) and TatA (αTatA) revealing the 37 kDa TatA–TatC complexes (black squares). The same adduct was also obtained when Bpa was incorporated into the N terminus of TatA (c, lanes 4 and 6). TatA oligomers (red stars) crosslinked through the N terminus of TatA were also obtained. In addition, TatA forms dimers independently of Bpa (c, lanes 8–14, grey arrow head). Open squares mark an adduct that by size consists of two TatC and one TatA molecule. (d) Model of the E. coli TatC structure highlighting in yellow the three residues that yielded pronounced tetramers of TatC (a).
