- A large conformational change of the translocation ATPase SecA.
A large conformational change of the translocation ATPase SecA.
Proceedings of the National Academy of Sciences of the United States of America (2004-07-17)
Andrew R Osborne, William M Clemons, Tom A Rapoport
PMID15256599
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.