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. 2020 Aug 18;9:e58622. doi: 10.7554/eLife.58622

Figure 3. Multibody refinement of ORCO1AAA.

(a) Overlay of ORCOPEN and ORCO1AAA illustrates a large conformational change of ORC2 and ORC3. ORC2·3·(5 WH) and ORC1·4·(5 AAA+) were designated as two bodies for Relion’s multibody refinement. (b) Principal component analysis revealed two prominent movements of ORCO1AAA highlighted in red and blue. (c) Component 1 undergoes twist movement of ORC2·3 across the ORC1 AAA+ domain. (d) Component 2 undergoes a pinch movement of ORC2·3 towards the ORC1 AAA+ domain. Multibody Refinement results of ORCO2WH and ORCOPEN are available in Figure 3—figure supplement 1. To validate the Multibody Refinement, Cryosparc’s 3D Variability analysis was performed and yielded the same prominent movements. The movements from Multibody Refinement and 3D variability can be visualized in Video 3.

Figure 3.

Figure 3—figure supplement 1. Relion’s Multibody Refinement (Nakane et al., 2018) of ORC conformations.

Figure 3—figure supplement 1.

Principal component analysis results for, ORCO2WH (a), and ORCOPEN (b). The most prominent movements for each conformation are twist and pinch motions.
Figure 3—figure supplement 2. Extension of ORC3 N-terminal α-helix in ORCOPEN.

Figure 3—figure supplement 2.

The N-terminal region of ORC3 in the ORCOPEN structures extends into a long α-helix compared to the other ORC conformations. The long α-helix likely contributes to the open conformation of the structure.