Extended Data Fig. 2: The N-helix and its role in keeping PINK1 monomeric.

a, The pseudokinases SgK223 (PDB: 5VE6) and SgK269 (PDB: 6BHC) were structurally characterised only recently^25,26, and contain a CTR similar to PINK1 that is complemented by an N-helix, in a highly analogous fashion now shown for PINK1. While conceptually similar, the organization of the N-helix on the CTR is however distinct. SgK223 and SgK269 utilize a cross-architecture to provide a dimerization interface, whereas the orientation in PINK1 is parallel to the αK helix of the CTR. b, SEC–MALS analysis of PhPINK1 with (amino acids 115–575) or without (amino acids 143–575) the N-helix. The shorter PhPINK1 construct tends to form less well-defined dimers, whereas the longer variant is a monomer. Experiments were performed three times with identical results. c, Previous TcPINK1 and PhPINK1 structures dimerized in the crystal lattice through the CTR, reflecting an available interaction surface since the N-helix was missing. TcPINK1 structures dimerized identically (left, only shown for PDB 5OAT¹¹). The relative orientation of PhPINK1 molecules in PDB 6EQI¹⁰ was different to TcPINK1 (middle). Right, PhPINK1(D334A) structure including the N-helix, for comparison. d, Schematic of the N-helix–CTR interaction, and situation in previous PINK1 structures, as identified in structures and in SEC–MALS.