Extended Data Figure 2. Interaction of segment-3 with blocked-head RLC and analysis of RLC photo-crosslink.

a, Segmented map highlighting latch and mortar regions (boxed), which are shown in more detail in panels b and c respectively. The position of phosphorylated serine (S20) in the latch (b) and in the mortar (c) are shown. This illustrates how phosphorylation would disrupt latch-segment-3 and mortar-RLC interactions respectively. d, Segmented map showing region of interest for panels e-g. e, ionic interactions between segment-3 and blocked-head RLC inter-lobe linker and blocked-head heavy chain. f, Hydrophobic interface where segment-3 crosses the blocked head RLC. g, Same view as e and f showing photo-crosslinker benzophenone-4-acetamide attached to C109 of blocked-head RLC and in close proximity to the aliphatic side chain of K1579 of segment 3 chain H. K1579 lies within crosslinked peptide L1554-E1583 ⁴². h, Segmented map (face view) to show the location (boxed) of i, which shows an alternative view of photo-crosslinker interaction and the ionic interaction between blocked head RLC E112 and segment 3 R1584. For clarity the non-involved chain of the coiled coil has been omitted in the close-up panels.