Цианобактерин

Description

Cyanobacterin is a chlorinated gamma-lactone, a secondary metabolite of the cyanobacterium Scytonema hofmanni. According to the chemical class, it belongs to linear non-peptides. The compound is known as a natural algaecide: it inhibits photosynthetic electron transport in eukaryotic algae and higher plants, acting at the level of photosystem II without affecting photosystem I.

Basic Attributes

• CAS No: 80902-00-7
• Chemical formula: C23H23ClO6
• Molecular weight: 430.881
• Exact weight: 430.88
• PSA specifications: 74.2
• XLogP3: 4.5
• Chemical class: other linear non-peptide

Mechanism of action

Cyanobacterin blocks the transfer of electrons in the oxygen-releasing chain of photosynthesis at the site of photosystem II - the same node where classical herbicides-inhibitors of photosynthesis of the triazine and urea series act. The growth of sensitive algae is inhibited at a concentration of about 5 µM. The compound acts on both higher plants (angiosperm) and eukaryotic microorganisms, but does not affect photosystem I, which indicates the specificity of the target.

Scope of application

Considered as a model compound for studying photosystem II inhibitors and as a natural algaecide for controlling algal and cyanobacterial blooms for research purposes. It is used in laboratory practice of phytophysiology and algology to study photosynthetic electron transport.

Origin and structure

The substance was first isolated from the culture of the freshwater filamentous cyanobacterium Scytonema hofmanni as an alkaloid-like secondary metabolite with pronounced phytotoxic activity. The molecular framework is a chlorine-substituted benzodioxole fragment connected to a γ-lactone ring and a methoxyphenyl group; This structure distinguishes cyanobacterin from the terpenoid and peptide classes of natural photosynthesis inhibitors.

Comparison with other photosystem II inhibitors

The target of cyanobacterin coincides with the target of synthetic herbicides of the triazine (atrazine, cyanazine) and urea series - the QB-binding pocket of the D1 protein of photosystem II. Moreover, cyanobacterin is not structurally similar to any of these classes, which makes it a convenient tool for studying alternative binding sites in the photosystem II protein complex and for searching for herbicides with a new mechanism for overcoming weed resistance.

Storage and handling

Like most chlorinated lactones of natural origin, the substance is stored in a place protected from light and moisture, in an airtight container, at a low temperature to avoid hydrolysis of the lactone cycle. The work is carried out using standard personal protective equipment for organic compounds with an unknown acute toxicity profile. This target specificity makes cyanobacterin a convenient control substance for screening new inhibitors of the photosynthetic apparatus in higher plants.