[Affinity capillary electrophoresis for screening proteins interacting with domoic acid]

Area of Science:

• Biochemistry
• Toxicology
• Analytical Chemistry

Background:

• Domoic acid (DA) is a potent marine neurotoxin responsible for amnesic shellfish poisoning.
• Understanding DA's interaction with biological macromolecules is crucial for elucidating its toxicity mechanisms.

Purpose of the Study:

• To qualitatively compare the interactions between domoic acid and nine important functional proteins using affinity capillary electrophoresis.
• To screen potential DA target proteins and provide foundational data for understanding DA's toxicological effects.

Main Methods:

• Affinity capillary electrophoresis (ACE) was employed with proteins as ligands and DA as the receptor.
• DA migration times were measured across varying protein concentrations to determine binding affinities.
• Relative interaction strengths were assessed by analyzing the slope of DA mobility ratio versus protein concentration graphs.

Main Results:

• Six out of nine tested proteins demonstrated interaction with domoic acid.
• The binding affinity order was determined as: human thrombin > cytochrome C > trypsin > immunoglobulin E (IgE) ≈ ribonuclease A > λ exonuclease.
• Ferritin, transferrin, and lectin showed no significant affinity for domoic acid.

Conclusions:

• Affinity capillary electrophoresis is an efficient and sensitive method for screening domoic acid-binding proteins.
• Identifying DA-protein interactions provides essential insights into the neurotoxin's mechanism of action and potential countermeasures.