Structural studies of a signal peptide in complex with signal peptidase I cytoplasmic domain: the stabilizing effect of membrane-mimetics on the acquired fold.

ABSTRACT: A protein destined for export from the cell cytoplasm is synthesized as a preprotein with an amino-terminal signal peptide. In Escherichia coli, typically signal peptides that guide preproteins into the SecYEG protein conduction channel are subsequently removed by signal peptidase I. To understand the mechanism of this critical step, we have assessed the conformation of the signal peptide when bound to signal peptidase by solution nuclear magnetic resonance. We employed a soluble form of signal peptidase, which laks the two transmembrane domains (SPase I Δ2-75), and the E. coli alkaline phosphatase signal peptide. Using a transferred NOE approach, we found clear evidence of a weak peptide-enzyme complex formation. The peptide adopts a U-turn shape originating from the proline residues with

SUBMITTER: De Bona P 

PROVIDER: S-EPMC3277640 | biostudies-literature | 2012 Mar

REPOSITORIES: biostudies-literature