Crystallographic analysis of Neisseria meningitidis PorB extracellular loops potentially implicated in TLR2 recognition

Christof Kattner, Deana Toussi, Jan Zaucha, Lee M. Wetzler, Nadine Rüppel, Ulrich Zachariae, Paola Massari (Lead / Corresponding author), Mikio Tanabe (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Among all Neisseriae species, Neisseria meningitidis and Neisseria gonorrhoeae are the only human pathogens, causative agents of bacterial meningitis and gonorrhoea, respectively. PorB, a pan-Neisseriae trimeric porin that mediates diffusive transport of essential molecules across the bacterial outer membrane, is also known to activate host innate immunity via Toll-like receptor 2 (TLR2)-mediated signaling. The molecular mechanism of PorB binding to TLR2 is not known, but it has been hypothesized that electrostatic interactions contribute to ligand/receptor binding. Strain-specific sequence variability in the surface-exposed loops of PorB which are potentially implicated in TLR2 binding, may explain the difference in TLR2-mediated cell activation in vitro by PorB homologs from the commensal Neisseria lactamica and the pathogen Neisseria meningitidis. Here, we report a comparative structural analysis of PorB from Neisseria meningitidis serogroup B strain 8765 (63% sequence homology with PorB from Neisseria meningitidis serogroup W135) and a mutant in which amino acid substitutions in the extracellular loop 7 lead to significantly reduced TLR2-dependent activity in vitro. We observe that this mutation both alters the loop conformation and causes dramatic changes of electrostatic surface charge, both of which may affect TLR2 recognition and signalling.
Original languageEnglish
Pages (from-to)440-447
Number of pages8
JournalJournal of Structural Biology
Volume185
Issue number3
Early online date19 Dec 2013
DOIs
Publication statusPublished - Mar 2014

Keywords

  • Outer membrane protein
  • Neisseriae
  • Crystal structure
  • Toll-like receptor

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