title: A large conformational change of the translocation ATPase SecA.
abstract: The 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-A 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.
authors.affiliation: Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Osborne
authors.forename: William M
authors.initials: WM
authors.lastname: Clemons
authors.forename: Tom A
authors.initials: TA
authors.lastname: Rapoport
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism; D001412:Bacillus subtilis / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D021381:Protein Transport; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; D000069816:SEC Translocation Channels; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins