BanLec

BanLec (also BanLec-I or Banana lectin) is a lectin from the jacalin-related lectin family isolated from the fruit of the bananas Musa acuminata and Musa balbisiana. BanLec is one of the predominant proteins in the pulp of ripe bananas and has binding specificity for mannose and mannose-containing oligosaccharides. A 2010 study reported that BanLec was a potent inhibitor of HIV replication.

Activity

BanLec has a number of similarities to Concanavalin A and binds to mannose-related carbohydrate structures. It was discovered due to its highly immunogenic properties—BanLec induces a strong IgG4 antibody response—and appears to be an important antigen involved in banana allergies.

BanLec protein expression can be induced by the plant hormone methyl jasmonate.

Structure and stability

BanLec exists as a homodimer of two identical 15 kDa subunits. The protein is highly stable, unfolding only at high temperatures

All jacalin-related lectins feature type I beta-prism folding motifs (the beta-prism I fold is like a perfect beta-prism with each side made up of a four-stranded greek key motif), but BanLec is the first jacalin-related lectin from the monocot family of plants, while all other members are dicots; other monocot mannose-binding lectins exhibit beta-prism II folding instead.