Giant Polyketide Synthases Biosynthesize a Marine Polyether Biotoxin.

Area of Science:

• Marine Biology
• Biochemistry
• Environmental Science

Background:

• Prymnesin toxins, a type of ladder polyether, are highly toxic non-proteinogenic substances.
• These toxins have been linked to significant environmental damage, including the 2022 Oder river catastrophe, and pose risks to human health.
• The biosynthetic pathways and enzymatic machinery responsible for prymnesin production have remained largely unknown.

Purpose of the Study:

• To elucidate the initial mechanisms by which algae produce prymnesin toxins.
• To identify and analyze the key enzymes involved in the biosynthesis of these potent toxins.
• To lay the groundwork for predicting and potentially mitigating future ecological impacts of algal toxins.

Main Methods:

• Advanced sequencing and assembly techniques were employed to analyze the genetic basis of toxin production.
• Identification and characterization of novel, large-scale polyketide synthases (PKS), PKZILLA-1 and PKZILLA-2.
• Confirmation and elucidation of stereocenters within the toxin structure.

Main Results:

• The study identified the largest known polyketide synthases, PKZILLA-1 and PKZILLA-2, crucial for prymnesin biosynthesis.
• These findings provide the first insights into the enzymatic machinery responsible for producing these complex and toxic compounds.
• The elucidation of stereocenters advances the understanding of the toxins' chemical structure and formation.

Conclusions:

• The research uncovers critical initial mechanisms in algal prymnesin toxin biosynthesis.
• This breakthrough enables further investigation into the production and properties of these highly toxic substances.
• Understanding toxin biosynthesis may lead to the prediction and management of future 'biblical plagues' caused by algal blooms.