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Substrate recognition of a structure motif for phosphorylcholine post-translational modification in Neisseria

Freda E-C Jen1, Christopher E Jones, Jennifer C Wilson

  • 1Institute for Glycomics, Griffith University, Gold Coast Campus, QLD 4222, Australia.

Biochemical and Biophysical Research Communications
|January 1, 2013
PubMed

Insights

Phosphorylcholine (ChoP) modifications on Neisseria meningitidis pili are crucial for bacterial virulence. This study identifies a specific D-A-S motif essential for ChoP modification, revealing key insights into host-pathogen interactions.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Neisseria meningitidis is a significant human pathogen causing meningitis and sepsis.
  • Pili are critical virulence factors in Neisseria species, mediating host-pathogen interactions.
  • Pilin proteins in N. meningitidis undergo post-translational modifications, including glycosylation and phosphorylcholine (ChoP) attachment, which are vital for colonization and invasion.

Purpose of the Study:

  • To investigate the substrate recognition mechanism of the phosphorylcholine transferase involved in pilin modification.
  • To identify the specific structural features of N. meningitidis pilin that dictate ChoP modification.
  • To understand the role of ChoP modifications in bacterial pathogenesis.

Main Methods:

  • Bioinformatic analysis to identify potential modification sites.
  • Site-directed mutagenesis to alter the pilin sequence.
  • Biochemical assays to assess ChoP transferase activity on modified pilin substrates.
  • Structural analysis to understand the local protein environment.

Main Results:

  • A specific D-A-S sequence motif, located after the disulfide bond in N. meningitidis pilin, was identified as the primary determinant for ChoP modification.
  • The charge of the residue within this motif and the local secondary structure are critical for recognition by the phosphorylcholine transferase.
  • Unlike in N. gonorrhoeae, ChoP modifications in N. meningitidis appear to be restricted to the C-terminus of the pilin protein.

Conclusions:

  • The D-A-S motif and its local structural context are essential for phosphorylcholine transferase substrate recognition in Neisseria meningitidis.
  • Understanding these specific modification mechanisms provides insights into N. meningitidis virulence and potential therapeutic targets.
  • The findings highlight differences in pilin modification between N. meningitidis and N. gonorrhoeae.

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