Fig. 1: Structures of a ZorA₅B₂ type I complex from Shewanella sp. strain ANA-3 and a ZorA₅B₂ type II complex from Sulfuricurvum kujiense.

a Schematic representation of Zorya I, Zorya II, and Zorya III loci. b Schematic representation of the domain composition of each Zorya subtype component. Domains were predicted using HHPRED. Only predictions with an e-value < 0.01 were included. For sequences with multiple domains predicted, the highest scoring one (bit score) is reported. c Cryo-EM volumes of a type I ZorA₅B₂ complex from Shewanella sp. strain ANA-3 (left) and a type II ZorA₅B₂ complex from Sulfuricurvum kujiense (right). ZorA subunits are displayed in shades of blue and the centrally located ZorB subunits are in shades of purple. The inner membrane (gray) was assigned based on the micelle density surrounding the complex at lower contour levels. d Models of type I ZorA₅B₂ from Shewanella sp. strain ANA-3 (left) and type II ZorA₅B₂ from Sulfuricurvum kujiense (right) depicted as cartoon representations and colored as in (a). e Structural alignment of the type I (gray) and type II (blue) ZorA₅B₂ complexes shows a conserved core across both Zorya types. f (i) Structural alignment of a single ZorA subunit from type I (gray) and type II (blue) and (ii) side-by-side comparison of these subunits in the same orientation colored in the rainbow (N-terminus blue, C-terminus red). g Comparison of ZorB dimers from type I (gray) or type II (blue), from the same view as the overlay displayed in (c), demonstrates the peptidoglycan binding domain differs in height (i) and orientation (ii) but the overall fold is consistent across Zorya types (iii). h (i) Structural conservation of the ZorAB core (left) and the polar ring formed from conserved serines/threonines of the ZorA pentamer surrounding the critically conserved aspartates on ZorB is consistent across type I (gray), type II (blue) ZorAB and MotAB (PDB 8UCS; pink) complexes (right). (ii) The polar residues of Shewanella sp. strain ANA-3 ZorA coordinate sodium at both sites that recruit the conserved aspartate of ZorB (top, gray), whereas C. sporogenes MotAB recruits sodium at a single site (pink, middle) and no metal or ion coordination is observed in Sulfuricurvum kujiense ZorAB (blue, bottom).