Extended Data Fig. 7: Structural and functional investigation of EcZorC and in vivo DNA degradation.
From: Structure and mechanism of the Zorya anti-phage defence system
a, SDS gel of purified ZorC wild type, ZorCE400A, ZorCH443A, ZorC∆CTD (deletion residues 487–560). Gel is representative of at least 3 replicates. b, Unsharpened Cryo-EM map of EcZorC. c, Local refinement of the EcZorC core domain with a soft mask, with the local resolution (in Å) estimated in cryoSPARC. d, Gold standard (0.143) Fourier Shell Correlation (GSFSC) curves of the local refined of the EcZorC core domain. e, Representative of a model and segments of the ZorC fitted into EM density map. The right panel is the final model of EcZorC built from a cryo-EM map. f, AlphaFold3-predicted ZorC model. g, Electrostatic distribution of EcZorC calculated from AlphaFold3-predicted model. h, In vitro interaction of EcZorC with 55 bp dsDNA (36.36% GC), 18 bp dsDNA (50.00% GC), 18 bp dsDNA (22.22% GC), 18 bp dsDNA (72.22% GC). Image is representative of at least 3 replicates. DNA sequences are shown below. i, AlphaFold3-predicted model of ZorC in complex with 18 bp dsDNA. The colour code (per-atom confidence estimate on a 0–100 scale) in f and i are same. j, Representative time-lapse images of E. coli cells expressing ParB-mSc in the presence or absence of EcZorI, exposed to Bas54-parS phage. In EcZorI-null cells, ParB foci are observed prior to cell lysis, whereas EcZorI-expressing cells lack ParB focus formation and survive phage infection. Scale bar is set to 2 µm.
