Canavalin
[3] The crystallization of jack bean seed proteins has been studied extensively since the early 20th century and was of particular interest to 1946 Nobel Prize in Chemistry laureate James B. Sumner,[4] though Sumner's group never fully characterized canavalin and it remained of little interest until its crystallization properties began to be studied in the 1970s.
However, in 1936 his student, S. Howell, working in his laboratory left out a sample of canavalin in a flask without regards for sterility.
Sumner and Howell were able to reproduce the crystals using sterile solutions of adding trypsin, chymotrypsin and other proteases to the canavalin.
The researchers reproduced Sumner's work and were able to produce large crystalline structures and describe some of canavalins biochemical properties.
Work in 1982 demonstrated that the native protein had a monomer that was cleaved in half by proteases and had mol weight of about 47,000.
They also found that the three cleaved monomers were distributed in a perfect 3-fold axis of symmetry in a molecule with a mol weight of about 142,000 [7] and consists of 445 amino acids.
Canavalin and phaseolin share 60% of the same amino acids and have similar tertiary and quaternary structures.
[6] Canavalins Response to Different Salt Concentrations Canavalin extracted from sword bean in distilled water has its monomer structure; however, when placed in high concentrations of NaCl and MgCl2, a change occurs between the monomeric to the trimeric form.
B-conglycinin is classified in the same group also has a trimer structure that can be purified and crystallized in the presence of high salt concentrations such as NaCl.
This suggests that in the presence of higher salt concentrations, the trimer structure of 7s globulin family is present.
If an engineered gene for canavalin can be inserted into a plant, then nutritionally enhanced seed storage proteins may exist.
This would create a possibility for improving and enhancing all of the leguminous plants, a major source of the world's dietary protein.
