Profiling of Haemophilus influenzae strain R2866 with carbohydrate-based covalent probes

Area of Science:

• Microbiology
• Chemical Biology
• Proteomics

Background:

• Haemophilus influenzae is a significant human pathogen.
• Understanding its protein targets is crucial for developing new therapeutics.
• Covalent probes offer a method for target identification and validation.

Purpose of the Study:

• To apply novel covalent probes for proteomic profiling of Haemophilus influenzae.
• To investigate the cellular localization and accessibility of target proteins.
• To identify potential antibacterial drug targets within H. influenzae.

Main Methods:

• Synthesis of four covalent probes based on d-galactosamine and d-glucosamine scaffolds.
• Application of probes for protein labeling in H. influenzae cell lysates and intact cells.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for target protein identification.

Main Results:

• Successful labeling of target proteins in both cell lysates and intact H. influenzae cells.
• Differential labeling patterns indicate probe penetration into the periplasm but not the cytoplasm.
• LC-MS/MS analysis identified predominantly nucleotide-binding proteins, including known antibacterial drug targets.

Conclusions:

• The developed covalent probes are effective tools for proteomic analysis of H. influenzae.
• The findings provide insights into protein accessibility within H. influenzae.
• This approach can aid in identifying molecular determinants of pathogenicity and novel drug targets.