Different Quaternary Structures of Human RECQ1 Are Associated with Its Dual Enzymatic Activity
Figure 5
Surface Rendering of 3D EM Reconstructions of RECQ1 Oligomers
Untagged wild-type RECQ1 + ssDNA (red); wild-type RECQ1+ssDNA (pink); K119R mutant RECQ1 + ATPγS (gold); and K119R mutant RECQ1 + ssDNA (white). All maps are shown using an arbitrary density threshold level of 3σ. The general shape of RECQ1 in the four functional states shows an overall similarity and consists of two ring-like densities “A” and “B,” interconnected by a larger ring-like structure “C.”
(A) Side-on views showing the basic three-ring structure with the middle ring “C” connecting the two outer rings with diagonally spanning densities.
(B) Head-on views of ring “A,” which has an outer diameter of 8 nm.
(C) Side-on views rotated by 90° about the y-axis relative to (B).
(D) Head-on views of ring “B,” which has approximately the same outer diameter as ring “A.”
The resolutions of the maps range from 22 Å for the tagged RECQ1 with ssDNA reconstruction to approximately 26 Å for the untagged RECQ1 with ssDNA reconstruction. Scale bar represents 10 nm [56].