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. Author manuscript; available in PMC: 2024 Oct 19.
Published in final edited form as: Mol Cell. 2023 Oct 12;83(20):3692–3706.e5. doi: 10.1016/j.molcel.2023.09.024

Figure 3. A phosphate sensor is a lynchpin in the Sen1 power stroke.

Figure 3.

(A) Structural superposition of the Sen1Hel–RNA–ADP–SO4 complex (tan) with the HsUpf1-RNA-ADP-AlF4 complex (grey).

(B) Structural superposition of the Sen1-RNA-ADP-S04 complex with ScSen1-ADP-Mg2+ complex, RSCB:5MZN. Close superposition of the RecA1 domains is observed. A 7.5 Å translocation is coincident with phosphate release. The blue sphere marks the position of Mg2+ in the ScSen1 -ADP-Mg2+ complex.

(C) Sen1 active site. Four residues from the RecA1 and RecA2 domains bind SO4, a mimic of the hydrolyzed phosphate prior to phosphate release.

(D) Active site structural superposition of ScSen1-ADP and CtSen1-RNA-ADP-SO4 complexes colored as indicated. Arrows show structural rearrangements of conserved gamma-phosphate sensing residues upon phosphate (SO4 mimic) release.