Skip to main content
. Author manuscript; available in PMC: 2022 May 8.
Published in final edited form as: Science. 2021 Jul 15;373(6556):768–774. doi: 10.1126/science.abi8976

Figure 3. Cryo-EM structure of TniQ-TnsC reveals how target-site selector protein, TniQ, binding at the target-site can interact with polymerizing TnsC.

Figure 3.

(A) TniQ from ShCAST is truncated with respect to I-F3 TniQ. Numbers indicate residue positions. Functional domains corresponding to the helix-turn-helix (HTH, orange) motif and zinc-finger ribbon (ZnF, pink) motif are indicated. The light blue domain (only in I-F3) corresponds to the C-terminal winged helix-turn-helix motif, and is missing in ShCAST TniQ. (B) Two copies of TniQ (orange/pink) interact with the head interface of the ATP-bound TnsC filament. Each monomer of TniQ interacts with two subunits (light/dark green) of TnsC. The Cryo-EM map shown is filtered according to local-resolution estimates (Bsoft). The N-terminus of TniQ is labeled ‘N’. (C) Homology models of the helix-turn-helix (HTH) and Zinc-finger (ZnF) motifs fit well with the observed cryo-EM density map. Cryo-EM density for ShCAST TniQ is shown, TnsC (green) and DNA (blue) are displayed in ribbon.