Decrypting the biochemical function of an essential gene from Streptococcus pneumoniae using ThermoFluor technology

Area of Science:

• Biochemistry
• Molecular Biology
• Protein Function Determination

Background:

• An essential gene in Streptococcus pneumoniae encodes a protein of unknown function.
• Understanding protein function is crucial for drug development and understanding biological pathways.

Purpose of the Study:

• To determine the biological function of an essential Streptococcus pneumoniae protein.
• To demonstrate the utility of ThermoFluor affinity screening for identifying protein ligands and functions.

Main Methods:

• Expression and purification of the recombinant Streptococcus pneumoniae protein.
• ThermoFluor affinity screening against a library of 3000 compounds.
• Sequence homology analysis and identification of conserved residues.
• Screening against generic drugs and natural products for covalent modifiers.

Main Results:

• The protein exists as a dimeric, cooperatively unfolding native-like state.
• Pyridoxal phosphate and pyridoxamine phosphate were identified as equilibrium binding ligands.
• Nucleotides and nucleotide sugars were also identified as ligands.
• Conserved residues involved in pyridoxal phosphate binding were identified through sequence comparison.
• The antifungal compound canescin A was found to be an irreversible covalent modifier.

Conclusions:

• The protein is likely a nucleoside diphospho-keto-sugar aminotransferase.
• ThermoFluor screening is an effective method for elucidating protein functions.
• The identified ligands and modifier provide insights into the protein's enzymatic activity and potential drug interactions.