The periplasmic chaperone SurA exploits two features characteristic of integral outer membrane proteins for selective
Gerrit Hennecke1, Jessica Nolte, Rudolf Volkmer-Engert
1Abteilung Molekulare Genetik und Präparative Molekularbiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstrasse 8, D-37077 Göttingen, Germany.
The Journal of Biological Chemistry
|April 21, 2005
Summary
The chaperone SurA specifically binds outer membrane proteins, distinguishing them from other proteins. This specificity, driven by aromatic residue patterns, is crucial for its role in outer membrane protein maturation.
Area of Science:
- Microbiology
- Protein Folding
- Cellular Biology
Background:
- SurA is an Escherichia coli periplasmic chaperone essential for outer membrane porin maturation.
- Its peptidyl-prolyl isomerase (PPIase) activity is dispensable, while chaperone activity is crucial.
- SurA exhibits substrate selectivity, unlike many cytoplasmic chaperones.
Purpose of the Study:
- To characterize the substrate specificity of SurA.
- To understand how SurA discriminates between outer membrane proteins and other substrates.
- To elucidate the role of SurA's chaperone function in outer membrane protein maturation.
Main Methods:
- Screening of cellulose-bound peptide libraries representing outer membrane proteins.
- Analysis of peptide binding requirements, including PPIase activity and proline presence.
- Investigation of SurA's association with the outer membrane.
Main Results:
- SurA binding is critically dependent on specific aromatic residue patterns and side-chain orientation.
- These features are more prevalent in integral outer membrane proteins.
- Substrate specificity is linked to SurA's chaperone function, independent of PPIase activity.
- SurA demonstrates association with the outer membrane.
Conclusions:
- SurA possesses specialized chaperone activity for outer membrane proteins.
- Aromatic residue patterns dictate SurA's substrate recognition.
- SurA facilitates outer membrane protein maturation by interacting with periplasmic folding intermediates.
- SurA is a key player in the biogenesis of essential outer membrane proteins.
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