Publication

Domain dynamics of the Bacillus subtilis peripheral preprotein translocase subunit SecA

Driessen, A. J. M., 1998, BIOCALORIMETRY. Ladbury, JE. & Chowdhry, BZ. (eds.). CHICHESTER: Wiley, p. 253-265 13 p.

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-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.

Original languageEnglish
Title of host publicationBIOCALORIMETRY
EditorsJE Ladbury, BZ Chowdhry
Place of PublicationCHICHESTER
PublisherWiley
Chapter18
Pages253-265
Number of pages13
ISBN (Print)0-471-97781-0
Publication statusPublished - 1998
EventConference on the Applications of Calorimetry in the Biological Sciences -
Duration: 1-Sep-1996 → …

Other

OtherConference on the Applications of Calorimetry in the Biological Sciences
Period01/09/1996 → …

Event

Conference on the Applications of Calorimetry in the Biological Sciences

01/09/1996 → …

Event: Other

    Keywords

  • DIFFERENTIAL SCANNING CALORIMETRY, DISTINCT ATP-BINDING, ESCHERICHIA-COLI, PROTEIN TRANSLOCATION, MEMBRANE, COMPLEMENTATION, IDENTIFICATION, VECTORS, DRIVEN, INVIVO

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