The crystal structure of the AAA domain of the ATP-dependent protease FtsH of Escherichia coli at 1.5 Å resolution

Eubacteria and eukaryotic cellular organelles have membrane-bound ATP-dependent proteases, which degrade misassembled membrane protein complexes and play a vital role in membrane quality control. The bacterial protease FtsH also degrades an interesting subset of cytoplasmic regulatory proteins, including σ32, LpxC, and λ CII. The crystal structure of the ATPase module of FtsH has been solved, revealing an α/β nucleotide binding domain connected to a four-helix bundle, similar to the AAA modules of proteins involved in DNA replication and membrane fusion. A sulfate anion in the ATP binding pocket mimics the β-phosphate group of an adenine nucleotide. A hexamer form of FtsH has been modeled, providing insights into possible modes of nucleotide binding and intersubunit catalysis.