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The conformation and function of a multimodular glycogen-degrading pneumococcal virulence factor

Alicia Lammerts van Bueren1, Elizabeth Ficko-Blean, Benjamin Pluvinage

  • 1Biochemistry & Microbiology, University of Victoria, Victoria, BC, Canada.

Structure (London, England : 1993)
|May 14, 2011
PubMed

Insights

Streptococcus pneumoniae uses the SpuA enzyme to degrade host glycogen, a process crucial for its virulence. Structural studies reveal how SpuA

Area of Science:

  • Microbiology
  • Structural Biology
  • Biochemistry

Background:

  • Streptococcus pneumoniae is a pathogenic bacterium responsible for various infections.
  • SpuA is a cell wall-associated enzyme critical for degrading host glycogen.
  • Glycogen degradation by SpuA has been linked to the virulence of Streptococcus pneumoniae.

Purpose of the Study:

  • To elucidate the molecular mechanisms of substrate recognition by the multimodular enzyme SpuA.
  • To understand the structural basis of SpuA's role in Streptococcus pneumoniae virulence.
  • To investigate the interplay between modules in complex carbohydrate-active enzymes.

Main Methods:

  • X-ray crystallography was employed to determine high-resolution structures.
  • Small-angle X-ray scattering (SAXS) provided insights into overall protein conformation.
  • Inhibitor binding studies were used to map substrate interaction sites.

Main Results:

  • The study reveals the intricate active site of SpuA and its substrate recognition features.
  • Conformational changes during carbohydrate binding by SpuA were characterized.
  • The cooperative interaction between SpuA's composite modules during glycogen degradation was demonstrated.

Conclusions:

  • SpuA's structure and function are key to Streptococcus pneumoniae's virulence.
  • Understanding SpuA provides insights into multimodular enzyme mechanisms.
  • This work contributes to the structural and functional framework of carbohydrate-active enzymes.

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