Allosteric Signalling in the Outer Membrane Translocation
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چکیده
PapC ushers are outer-membrane proteins enabling assembly and secretion of P pili in uropathogenic E. coli. Their translocation domain is a large -barrel occluded by a plug domain, which is displaced to allow the translocation of pilus subunits across the membrane. Previous studies suggested that this gating mechanism is controlled by a -hairpin and an -helix. To investigate the role of these elements in allosteric signal communication we developed a method combining evolutionary and molecular dynamics studies of the native translocation domain and mutants lacking the hairpin and/or -helix. Analysis of a hybrid residue interaction network suggests distinct regions (residue communities ) within the translocation domain (especially around 1214) linking these elements, thereby modulating PapC gating. Antibiotic sensitivity and electrophysiology experiments on a set of alanine-substitution mutants confirmed functional roles for four of these communities. This study illuminates the gating mechanism of PapC ushers and its importance in maintaining outermembrane permeability.
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Figures and figure supplements Allosteric signalling in the outer membrane translocation domain of PapC usher Irene
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Allosteric signalling in the outer membrane translocation domain of PapC usher
PapC ushers are outer-membrane proteins enabling assembly and secretion of P pili in uropathogenic E. coli. Their translocation domain is a large β-barrel occluded by a plug domain, which is displaced to allow the translocation of pilus subunits across the membrane. Previous studies suggested that this gating mechanism is controlled by a β-hairpin and an α-helix. To investigate the role of thes...
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تاریخ انتشار 2014