FIG 1.

ZipA cross-links FtsZ at noncanonical residues. (A) Anti-ZipA (α-ZipA) and anti-FtsZ (α-FtsZ) Western blots of cell lysates of strain WM1074 carrying pUltra-pBpF, pKG110-FtsZ, and pDSW210-ZipA-GFP or derived constructs containing indicated Bpa substitutions in ZipA. CLS containing ZipA-GFP and FtsZ readily formed for residues R314X, Q317X, and E295X, but can be observed for all constructs with enhanced exposure (bottom panel). Cross-linking efficiency relative to ZipA(R314X)-GFP is indicated below +UV lanes and was normalized by total protein levels and ZipA-GFP expression for each strain. (B) Crystal structure of ZipA (gray) bound to the FtsZ CTP (teal) (16) annotated with each noncanonical cross-linking residue (blue). Asterisks indicate relative cross-linking strength with more asterisks indicated higher cross-linking strength.