About the Lectin

The bark of the black mulberry tree (Morus nigra)
accumulates large quantities of a galactose-specific (Morniga G) and a mannose (Man)-specific (Morniga M) jacalinrelated
lectin. Morniga G resembles jacalin with respect to its
molecular structure, specificity, and co-and posttranslational
processing indicating that it follows the secretory pathway
and eventually accumulates in the vacuolar compartment. In
contrast, Morniga M represents a novel type of highly active
Man-specific jacalin-related lectin that is synthesized without
signal peptide or other vacuolar targeting sequences, and
accordingly, accumulates in the cytoplasm. The isolation and
cloning, and immunocytochemical localization of Morniga G
and Morniga M not only demonstrates that jacalin-related
lectins act as vegetative storage proteins in bark, but also
allows a detailed comparison of a vacuolar galactose-specific
and a cytoplasmic Man-specific jacalin-related lectin from
a single species. Moreover, the identification of Morniga M
provides the first evidence, to our knowledge, that bark
cells accumulate large quantities of a cytoplasmic storage
protein. In addition, due to its high activity, abundance, and
ease of preparation, Morniga M is of great potential value
for practical applications as a tool and bioactive protein in
biological and biomedical research ¹ .

REFERENCES

1. Van Damme, Els, et al.(2002) Plant Physiology. 130 : 757-769