YirB blocks interaction between Spx and YjbH in vitro. Data from an in vitro pulldown assay of YjbH-Spx-Strep (strp) protein interaction in the absence and presence of purified YirB-His. R, reaction; FT, column flowthrough fraction; W2, second wash fraction from column; E, elution. YjbH protein is used as marker in the far right lane. M, prestained molecular mass (kDa) marker.