Purification of a functional mature region from a SecA-dependent preprotein.
Most of the bacterial proteins that are active in extracytoplasmic locations are translocated through the inner membrane by the Sec translocase. Translocase comprises a membrane "pore" and the peripheral ATPase SecA. Where preproteins bind to SecA and how they activate translocation ATPase remains elusive. To address this central question we have purified to homogeneity the mature and preprotein parts of an exported protein (pCH5EE). pCH5EE satisfies a minimal size required for protein translocation and its membrane insertion is SecA-dependent. Purified pCH5EE and CH5EE can form physical complexes with SecA and can functionally suppress the elevated ATPase of a constitutively activated mutant. These properties render pCH5EE and CH5EE unique tools for the biochemical mapping of the preprotein binding site on SecA.
Baud
Catherine
C
Institute of Molecular Biology and Biotechnology, FORTH and Department of Biology, University of Crete, P.O. Box 1527, GR-711 10 Iraklio, Crete, Greece.
Papanikou
Efrosyni
E
Karamanou
Spyridoula
S
Sianidis
Giorgos
G
Kuhn
Andreas
A
Economou
Anastassios
A
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001665:Binding Sites; D003001:Cloning, Molecular / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics; D026901:Membrane Transport Proteins / Q000378:metabolism*; D011485:Protein Binding; D011498:Protein Precursors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D021382:Protein Sorting Signals; D021381:Protein Transport; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D000069816:SEC Translocation Channels; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins