Structure and evolution of ricin B chain.

Area of Science:

• Biochemistry
• Molecular Biology
• Toxicology

Background:

• Ricin is a potent toxin from Ricinus communis.
• It consists of a B subunit for cell attachment and an A subunit for enzymatic activity.
• The B subunit targets cell surface receptors.

Purpose of the Study:

• To investigate the evolutionary origins of the ricin B subunit.
• To understand the structural basis of its sugar-binding function.

Main Methods:

• Amino acid sequence data analysis.
• High-resolution structural analysis of the ricin B subunit.

Main Results:

• The ricin B subunit is a product of multiple gene duplications.
• It contains two distinct sugar-binding domains.
• Each domain is formed by three repetitions of an ancient galactose-binding peptide.

Conclusions:

• The structure of the ricin B subunit reflects a stepwise evolutionary process.
• Understanding its structure provides insights into toxin evolution and function.