PrlA4 prevents the rejection of signal sequence defective preproteins by stabilizing the SecA–SecY interaction during the initiation of translocation
| Autor: | Janet L. Huie, P. Fekkes, André Boorsma, Arnold J. M. Driessen, Jeroen P.W. van der Wolk, Thomas J. Silhavy |
|---|---|
| Přispěvatelé: | Groningen Biomolecular Sciences and Biotechnology |
| Jazyk: | angličtina |
| Rok vydání: | 1998 |
| Předmět: |
Signal peptide
SecA Mutant Chromosomal translocation Protein Sorting Signals environment and public health General Biochemistry Genetics and Molecular Biology Bacterial Proteins Translocase Protein Precursors Molecular Biology Adenosine Triphosphatases SecYEG Translocon SecA Proteins General Immunology and Microbiology biology Membrane transport protein Escherichia coli Proteins General Neuroscience Membrane Transport Proteins SecY Biological Transport Cell biology Biochemistry Cytoplasm biology.protein signal sequence proof-reading bacteria SEC Translocation Channels Research Article Bacterial Outer Membrane Proteins |
| Zdroj: | EMBO Journal, 17(13), 3631-3639. Wiley |
| ISSN: | 0261-4189 |
| Popis: | In Escherichia coli, precursor proteins are translocated across the cytoplasmic membrane by translocase. This multisubunit enzyme consists of a preprotein-binding and ATPase domain, SecA, and the SecYEG complex as the integral membrane domain. PrlA4 is a mutant of SecY that enables the translocation of preproteins with a defective, or missing, signal sequence. Inner membranes of the prlA4 strain efficiently translocate Delta8proOmpA, a proOmpA derivative with a non-functional signal sequence. Owing to the signal sequence mutation, Delta8proOmpA binds to the translocase with a lowered affinity and the recognition is not restored by the prlA4 SecY. At the ATP-dependent initiation of translocation, the binding affinity of SecA for SecYEG is lowered causing the premature loss of bound preproteins from the translocase. The prlA4 membranes, however, bind SecA with a much higher affinity than the wild-type, and during initiation, the SecA and preprotein remain bound at the translocation site allowing an improved efficiency of translocation. It is concluded that the prlA4 strain prevents the rejection of defective preproteins from the export pathway by stabilizing SecA at the SecYEG complex. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text