Domain dynamics of the Bacillus subtilis peripheral preprotein translocase subunit SecADriessen, A. J. M., 1998, BIOCALORIMETRY. Ladbury, JE. & Chowdhry, BZ. (eds.). CHICHESTER: Wiley, p. 253-265 13 p.
Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Academic › peer-review
The homodimeric SecA protein is the peripheral subunit of the preprotein translocase in bacteria. It promotes the preprotein translocation across the cytoplasmic membrane by nucleotide-modulated co-insertion and de-insertion into the integral domain of the translocase. SecA has two essential nucleotide binding sites (NBS): the high-affinity NBS-I resides in the amino-terminal domain of the protein and the low-affinity NBS-II is localized at 2/3 of the protein sequence. The nucleotide bound states of soluble SecA were studied by differential scanning calorimetry (DSC). Thermal unfolding reveals that the amino- and carboxy-terminal halves of SecA unfold independently with a transition midpoint of 49 and 40 degrees C, respectively. Binding of ADP to NBS-I increased the interaction between the two domains, whereas binding of AMPPNP does not influence this interaction. When ADP binds both NBS-I and NBS-II, SecA seems to have a more compact globular conformation, whereas binding of AMP-PNP seems to cause a more extended conformation. It is concluded that SecA is a two-domain protein and that the interaction between both domains is modulated by nucleotides. The compact ADP-bound conformation may resemble the membrane-de-inserted state of SecA, while the more extended ATP bound conformation may correspond to the membrane-inserted form of SecA.
|Title of host publication||BIOCALORIMETRY|
|Editors||JE Ladbury, BZ Chowdhry|
|Place of Publication||CHICHESTER|
|Number of pages||13|
|Publication status||Published - 1998|
|Event||Conference on the Applications of Calorimetry in the Biological Sciences - |
Duration: 1-Sep-1996 → …
|Other||Conference on the Applications of Calorimetry in the Biological Sciences|
|Period||01/09/1996 → …|
Conference on the Applications of Calorimetry in the Biological Sciences
01/09/1996 → …
- DIFFERENTIAL SCANNING CALORIMETRY, DISTINCT ATP-BINDING, ESCHERICHIA-COLI, PROTEIN TRANSLOCATION, MEMBRANE, COMPLEMENTATION, IDENTIFICATION, VECTORS, DRIVEN, INVIVO