Osborne, Andrew R.Clemons, William M. Jr.Rapoport, Tom A.2019-10-142004Osborne, A. R., W. M. Clemons, and T. A. Rapoport. 2004. “A Large Conformational Change of the Translocation ATPase SecA.” Proceedings of the National Academy of Sciences 101 (30): 10937–42. doi:10.1073/pnas.0401742101.0027-84240744-28311091-6490http://nrs.harvard.edu/urn-3:HUL.InstRepos:41543123The ATPase SecA mediates the posttranslational translocation of a wide range of polypeptide substrates through the SecY channel in the cytoplasmic membrane of bacteria. We have determined the crystal structure of a monomeric form of Bacillus subtilis SecA at a 2.2-Angstrom resolution. A comparison with the previously determined structures of SecA reveals a nucleotide-independent, large conformational change that opens a deep groove similar to that in other proteins that interact with diverse polypeptides. We propose that the open form of SecA represents an activated state.en-USJournal Article2019-10-1410.1073/pnas.0401742101