Allosteric signalling in the outer membrane translocation domain of PapC usher

نویسندگان

  • Irene Farabella
  • Thieng Pham
  • Nadine S Henderson
  • Sebastian Geibel
  • Gilles Phan
  • David G Thanassi
  • Anne H Delcour
  • Gabriel Waksman
  • Maya Topf
چکیده

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 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 β-hairpin and/or the α-helix. Analysis of a hybrid residue interaction network suggests distinct regions (residue 'communities') within the translocation domain (especially around β12-β14) 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 outer-membrane permeability.

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Allosteric Signalling in the Outer Membrane Translocation

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عنوان ژورنال:

دوره 3  شماره 

صفحات  -

تاریخ انتشار 2014