1. Independent domain assembly in a trapped folding intermediate of multimeric outer membrane secretins.
- Author
-
Guilvout I, Chami M, Disconzi E, Bayan N, Pugsley AP, and Huysmans GH
- Subjects
- Amino Acid Substitution, Bacterial Outer Membrane Proteins chemistry, Bacterial Outer Membrane Proteins genetics, Bacterial Proteins chemistry, Bacterial Proteins genetics, Bacterial Secretion Systems physiology, Escherichia coli genetics, Escherichia coli metabolism, Gene Expression, Klebsiella oxytoca metabolism, Membrane Proteins chemistry, Membrane Proteins genetics, Protein Binding, Protein Folding, Protein Multimerization, Protein Structure, Secondary, Protein Structure, Tertiary, Pseudomonas aeruginosa chemistry, Pseudomonas aeruginosa metabolism, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins ultrastructure, Structural Homology, Protein, Structure-Activity Relationship, Bacterial Outer Membrane Proteins ultrastructure, Bacterial Proteins ultrastructure, Klebsiella oxytoca chemistry, Membrane Proteins ultrastructure
- Abstract
The outer membrane portal of the Klebsiella oxytoca type II secretion system, PulD, is a prototype of a family of proteins, the secretins, which are essential components of many bacterial secretion and pilus assembly machines. PulD is a homododecamer with a periplasmic vestibule and an outer chamber on either side of a membrane-spanning region that is poorly resolved by electron microscopy. Membrane insertion involves the formation of a dodecameric membrane-embedded intermediate. Here, we describe an amino acid substitution in PulD that blocks its assembly at this intermediate "prepore" stage. Electron microscopy indicated that the prepore has an apparently normal periplasmic vestibule but a poorly organized outer chamber. A peptide loop around this amino acid appears to be important for the formation/stability of the fully folded complex. A similar assembly intermediate results from creation of the same amino acid substitution in the Pseudomonas aeruginosa secretin XcpQ., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF