Structure of a Synaptic γδ Resolvase Tetramer Covalently Linked to Two Cleaved DNAs Weikai Li, Satwik Kamtekar, Yong Xiong, Gary J. Sarkis, Nigel D. F. Grindley, Thomas A. Steitz

This supplement contains:

Materials and Methods
Figs. S1 to S4
Movies S1 to S4
References and Notes

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• Movie 1
  The structure of the γδ resolvase mutant - DNA complex. The coloring and denotations are the same as in Figure 3.

• Movie 2
  DNA cleavage facilitated by the tertiary structural changes from the pre-synaptic to the synaptic state. One of the subunits and its bound DNA in the presynaptic and synaptic complexes are aligned by their E-helices and DNA binding domains. The change of tertiary structure is modeled using MORPH (S11). Ser10 (blue and red spheres) approaches Ade20 (red stick) when the catalytic domain moves relative to the E-helix. This movement overcomes the spatial barrier for the cleavage reaction.

• Movie 3
  Modeled structural transition from the pre-synaptic to the synaptic complex and the hypothesized "subunit rotation" model. Two pre-synaptic site I dimers are aligned with the synaptic tetramer by the vertical dyad axis and the structural transition is modeled using the program MORPH (S11). The movements involve the sliding of E-helices along each other, scissor-like opening of an E-helix pair, and rotation of catalytic domains relative to E-helices. The proposed subunit rotation of strand exchange is shown viewed along the flat interface.

• Movie 4
  Subtle changes at the flat interface during subunit rotation. The modeling of interface sidechain changes upon subunit rotation derived from 20 cycles of energy minimization at every 10% of rotation was carried out as described in Figure S3. The primary structural changes within the subunits that occur during the subunit rotation seem to be changes in the sidechain rotamers in order to reduce van der Waals repulsion.