Skip to main content
. Author manuscript; available in PMC: 2010 Jul 13.
Published in final edited form as: Structure. 2010 Jan 13;18(1):127. doi: 10.1016/j.str.2009.10.020

Figure 5.

Figure 5

Conformation of the -1 sugar during TopIB catalysis. (A) The -1Ade sugar in the vTopIB-DNA-vanadate complex. The backbone torsion angle γ (the C3′-C4′-C5′-O5′ dihedral angle) adopts a trans configuration, placing O5′ in position for axial coordination of vanadium and in position for hydrogen-bonding by Lys167 and Arg130. The sugar also adopts an RNA-like C3′-endo pucker. (B) The corresponding sugar in a pre-cleavage complex of human TopIB (Y723F mutant) bound to DNA (PDB code 1A35). Here, the γ angle is close to the standard value of -60°, and the sugar is C2′-endo. The phosphate has not yet rotated and O5′ is not in position for interaction with Lys532 and Arg488.