Figure 4. (A) CTCF ZF8-9 spans across the DNA phosphate backbone (A).
Two views of ZF4-9, displayed by the crystallographic heat map, from low-to-high thermal B-factor (blue, cyan, green, and yellow).
(B-D) Aligned structures of ZF5-8 (B), ZF6-8 (C), and ZF7-8 (D) against a reference DNA molecule.
(E) Superimposition of 4-finger structures of ZF4-7 and ZF5-8 indicates that the C-terminal ZF7 lies in the major groove whereas ZF8 spans across the minor groove of DNA. See also Figure S4.
(F) Superimposition of four fragments of two-finger structures, ZF4-5, ZF5-6, ZF6-7 and ZF7-8, reveals that the C-terminal ZF8 swings to the right whereas the rest swing to the left.
(G) Enlarged linker regions between ZF6-7 and ZF7-8, with the alignment of linker sequences.
(H) Superimposition of DNA-bound ZF6-7 and DNA-free ZF6-7 (PDB 2CT1).