Effects of detergents on the oligomeric structures of hemolytic lectin CEL-III as determined by small-angle X-ray scattering.

Hemolytic lectin CEL-III isolated from the sea cucumber Cucumaria echinata forms transmembrane pores by self-oligomerization in target cell membranes. It also formed soluble oligomers in aqueous solution upon binding with specific carbohydrates under conditions of high pH and a high salt concentration. The size of the soluble CEL-III oligomers decreased when treated with detergents such as Triton X-100 and SDS. Small-angle X-ray scattering measurements suggested that the dissociated unit of the oligomer was a tightly associated CEL-III heptamer. Without detergents in solution, these heptamers further assembled into larger 21mer oligomers, comprising three heptamers held together by relatively weak hydrophobic interactions.