Subcellular fractions of CU1000N (wild type, wt) (A) and of Aa3341 and Aa3346 (B), which are tadZ mutants producing AaTadZΔA1 and AaTadZΔA2 from pBP346 and pBP352, respectively, were prepared by differential detergent solubilization and ultracentrifugation, as described in materials and methods. Immunoblots were probed with α-TadZ antisera. Soluble (S), inner membrane (IM), and outer membrane (OM) fractions are indicated.