Substrate Trapping in the Siderophore Tailoring Enzyme PvdQ

Area of Science:

• Microbiology
• Structural Biology
• Biochemistry

Background:

• Pseudomonas aeruginosa utilizes siderophore biosynthesis, particularly pyoverdine, to enhance virulence.
• The enzyme PvdQ is crucial in the pyoverdine pathway, cleaving a myristoyl anchor from a precursor.
• Targeting siderophore biosynthesis presents a promising strategy for developing new antimicrobial therapies.

Purpose of the Study:

• To characterize the structure and function of PvdQ, an enzyme involved in pyoverdine biosynthesis.
• To investigate a circularly permuted variant of PvdQ (cpPvdQ) for potential therapeutic applications.
• To elucidate the binding interactions between PvdQ and its pyoverdine precursor.

Main Methods:

• X-ray crystallography was used to determine the high-resolution structures of wild-type PvdQ and a mutant form.
• Biochemical assays were employed to assess the activity and selectivity of PvdQ and its variants.
• Structural analysis of the PvdQ-precursor complex provided insights into substrate binding.

Main Results:

• A circularly permuted PvdQ (cpPvdQ) retained wild-type activity, selectivity, and structure, bypassing self-processing.
• The X-ray crystal structure of an inactive mutant complexed with the pyoverdine precursor PVDIq revealed a specific binding pocket.
• This is the first reported structure of a pyoverdine precursor bound to its biosynthetic enzyme.

Conclusions:

• The structural and functional characterization of PvdQ and its cpPvdQ variant offers insights into pyoverdine biosynthesis.
• Understanding the specific binding interactions can inform the design of novel inhibitors targeting PvdQ.
• These findings have significant implications for developing new drugs against Pseudomonas aeruginosa infections.