A novel prenyltransferase from Paracoccus denitrificans

Area of Science:

• Biochemistry
• Enzymology
• Microbial Metabolism

Background:

• Polyprenyl diphosphates are crucial isoprenoid compounds involved in various biological processes.
• Understanding the enzymes responsible for their synthesis is key to elucidating metabolic pathways.
• Paracoccus denitrificans is a bacterium with potential for novel enzyme discovery.

Purpose of the Study:

• To identify and characterize a novel polyprenyltransferase from Paracoccus denitrificans.
• To determine the substrate specificity and catalytic activity of the newly found enzyme.
• To investigate the role of this enzyme in the bacterium's isoprenoid biosynthesis pathway.

Main Methods:

• Partial purification of the polyprenyltransferase enzyme from Paracoccus denitrificans extracts.
• Enzymatic assays using various polyprenyl diphosphate substrates and isopentenyl diphosphate.
• Analysis of reaction products to identify the synthesized prenyl diphosphates.
• Investigation of cofactor requirements, including detergent dependency.

Main Results:

• A novel polyprenyltransferase catalyzing the formation of Z-double bonds was identified and partially purified.
• The enzyme demonstrated a consecutive condensation activity, using EE-farnesyl diphosphate as a primer.
• The final product identified was EE-farnesyl-all-Z-hexaprenyl diphosphate (ZE-mixed nonaprenyl diphosphate).
• The enzyme accepted a range of substrates, including neryl diphosphate and ZEE-geranylgeranyl diphosphate.
• Detergent, such as Triton X-100, was found to be essential for enzyme activity.
• The formation of ZE-mixed undecaprenyl diphosphate, a precursor for bacterial sugar-carrier lipids, was not observed.

Conclusions:

• Paracoccus denitrificans possesses a unique polyprenyltransferase with specific Z-double bond forming capabilities.
• This enzyme synthesizes ZE-mixed nonaprenyl diphosphate, distinct from the typical bacterial sugar-carrier lipid precursor.
• The findings contribute to the understanding of diverse isoprenoid biosynthesis pathways in bacteria.