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Helicobacter pylori cell binding factor 2: Insights into domain motion

Vankadari Naveen1, Chen-Hsi Chu2, Bo-Wei Chen2

  • 1Molecular Cell Biology, Taiwan International Graduate Program, Graduate Institute of Life Sciences, National Defense Medical Center and Academia Sinica, Taipei 115, Taiwan; Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.

Journal of Structural Biology
|February 7, 2016
PubMed

Insights

Helicobacter pylori cell binding factor 2 (HpCBF2) is a virulence factor with peptidyl-prolyl cis-trans isomerase (PPIase) activity. Structural analysis reveals its homodimeric form and domain motion crucial for its chaperone function.

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Helicobacter pylori cell binding factor 2 (HpCBF2) is an antigenic virulence factor.
  • HpCBF2 belongs to the SurA-like peptidyl-prolyl cis-trans isomerase family, impacting gastrointestinal tract pathogenicity.
  • HpCBF2 exhibits peptidyl-prolyl cis-trans isomerase (PPIase) activity and may function as a periplasmic chaperone.

Purpose of the Study:

  • To measure the isomerization and chaperone activity of HpCBF2.
  • To determine the crystal structure of HpCBF2 in complex with an inhibitor.
  • To investigate the structural basis for HpCBF2's function.

Main Methods:

  • X-ray crystallography at 2.4Å resolution to determine the structure of HpCBF2-inhibitor complex.
  • Measurement of HpCBF2's isomerization and chaperone activity.
  • Small-angle X-ray scattering (SAXS) experiments to analyze domain motion.

Main Results:

  • The crystal structure revealed HpCBF2 as a homodimer with a central hydrophobic cavity.
  • Each monomer comprises a PPIase and a chaperone domain, with chaperone domains exhibiting a domain-swap.
  • SAXS data indicated domain motion between apo- and inhibitor-bound states, suggesting flexibility for peptide binding.

Conclusions:

  • HpCBF2 forms a unique homodimeric structure with distinct PPIase and chaperone domains.
  • The observed domain motion is likely essential for both PPIase activity and chaperone-mediated refolding.
  • Understanding HpCBF2 structure and dynamics offers insights into H. pylori pathogenicity and potential therapeutic targets.
Keywords:
Cell-binding factor 2ChaperoneDomain motionHelicobacter pyloriPPIase

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