Identification and characterization of the Staphylococcus aureus gene cluster coding for staphyloferrin A

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• Siderophores are crucial for bacterial growth in iron-limited conditions.
• Staphylococcus aureus, a pathogen, produces four siderophores with unknown genetic data.
• Staphyloferrin A is a prevalent siderophore in S. aureus.

Purpose of the Study:

• To characterize the gene cluster for staphyloferrin A production in S. aureus.
• To elucidate the biosynthesis pathway of staphyloferrin A.
• To identify key enzymes involved in staphyloferrin A synthesis.

Main Methods:

• Gene cluster expression in a heterologous host (Escherichia coli).
• In vitro reconstitution of staphyloferrin A biosynthesis.
• Purification and characterization of key enzymes (SfnaD and SfnaB).

Main Results:

• The gene cluster responsible for staphyloferrin A production was identified.
• Staphyloferrin A biosynthesis was successfully reconstituted in vitro.
• Two enzymes, SfnaD and SfnaB, were identified as key in the nonribosomal peptide synthetase independent siderophore (NIS) pathway.
• The pathway involves condensation of citric acid and d-ornithine.

Conclusions:

• Staphyloferrin A is synthesized via the NIS pathway, distinct from typical nonribosomal peptide synthetases.
• SfnaD and SfnaB are essential enzymes in staphyloferrin A biosynthesis.
• Understanding this pathway provides insights into S. aureus virulence and potential therapeutic targets.