Prepore Stability Controls Productive Folding of the BAM-independent Multimeric Outer Membrane Secretin PulD
| Autor: | Mohamed Chami, Julia Chamot-Rooke, Sébastien Brier, Gerard H. M. Huysmans, Véronique Hourdel, Ingrid Guilvout, Anthony P. Pugsley, Olivera Francetic |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Protein Folding Protein Conformation Equilibrium unfolding Protomer Plasma protein binding Biochemistry 03 medical and health sciences Protein structure Escherichia coli Amino Acid Sequence Molecular Biology Sequence Homology Amino Acid 030102 biochemistry & molecular biology Protein Stability Chemistry Escherichia coli Proteins Cell Biology Crystallography 030104 developmental biology Dodecameric protein Membrane protein Protein Structure and Folding Mutation Mutagenesis Site-Directed Biophysics Mutant Proteins Protein folding Protein Multimerization Bacterial outer membrane Bacterial Outer Membrane Proteins Protein Binding |
| Zdroj: | Journal of Biological Chemistry. 292:328-338 |
| ISSN: | 0021-9258 |
| Popis: | Members of a group of multimeric secretion pores that assemble independently of any known membrane-embedded insertase in Gram-negative bacteria fold into a prepore before membrane-insertion occurs. The mechanisms and the energetics that drive the folding of these proteins are poorly understood. Here, equilibrium unfolding and hydrogen/deuterium exchange monitored by mass spectrometry indicated that a loss of 4–5 kJ/mol/protomer in the N3 domain that is peripheral to the membrane-spanning C domain in the dodecameric secretin PulD, the founding member of this class, prevents pore formation by destabilizing the prepore into a poorly structured dodecamer as visualized by electron microscopy. Formation of native PulD-multimers by mixing protomers that differ in N3 domain stability, suggested that the N3 domain forms a thermodynamic seal onto the prepore. This highlights the role of modest free energy changes in the folding of pre-integration forms of a hyperstable outer membrane complex and reveals a key driving force for assembly independently of the β-barrel assembly machinery. |
| Databáze: | OpenAIRE |
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