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Histidine Residues at the Active Site of the Pasteurella multocida Toxin

Gillian D Pullinger1, Alistair J Lax

  • 1King's College London, Dental Institute, Department of Microbiology, London SE1 9RT, UK.

The Open Biochemistry Journal
|October 25, 2008
PubMed

Insights

Investigating histidine residues in Pasteurella multocida toxin (PMT) revealed that H1205 is crucial for its mitogenic activity. Other histidine mutations had varying or minimal effects on PMT function.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Microbiology

Background:

  • The mitogenic Pasteurella multocida toxin (PMT) is a key virulence factor.
  • Understanding the molecular mechanisms of PMT activity is essential for developing interventions.

Purpose of the Study:

  • To identify critical histidine residues within the active site of PMT.
  • To elucidate the role of specific histidine residues in PMT's mitogenic function.

Main Methods:

  • Site-directed mutagenesis of specific histidine residues (H1202, H1205, H1223, H1228) in PMT.
  • Assaying the mitogenic activity of the mutated PMT variants.

Main Results:

  • Mutation of H1205 resulted in a complete loss of PMT activity.
  • Mutation of H1223 showed a substitution-dependent effect on activity.
  • Mutations at H1202 and H1228 had minimal impact on PMT function.

Conclusions:

  • Histidine 1205 is essential for the mitogenic activity of Pasteurella multocida toxin.
  • Specific histidine residues play distinct roles in PMT's enzymatic function and mitogenic potential.
Keywords:
G-proteinsPMTPasteurella multocidadomain structurehistidine residuestoxin

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