The bacterial heat shock locus HsIU ATPase and HsIV peptidase together form an ATP-dependent HsIVU protease. Crystal structures show that HsIU forms a hexamer with a pore at one end and HsIV forms a dodecamer with translocation pores at both ends of two back-to-back stacked hexameric rings. Consistent with three electron microscopic studies and one small-angle X-ray scattering study, three crystal structures show that the nucleotide-binding domains of HsIU bind to HsIV and that the pores of the peptidase and ATPase are next to each other and aligned. A fourth crystal structure shows a radically different quaternary arrangement. Here I present a crystallographic analysis of the fourth structure to show that it contained a crystallographic origin shift and a mistake in space group assignment. Once these errors are corrected, a quaternary arrangement that is similar to those observed in the other structures emerges.