HOMOLOGY BETWEEN JACALIN AND ARTOCARPIN FROM JACKFRUIT (ARTOCARPUS-INTEGRIFOLIA) SEEDS - PARTIAL SEQUENCE AND PRELIMINARY CRYSTALLOGRAPHIC STUDIES OF ARTOCARPIN

Jacalin and artocarpin, the two lectins from jackfruit (Artocarpus int egrifolia) seeds, have different physicochemical properties and carboh ydrate-binding specificities. However, comparison of the partial amino -acid sequence of artocarpin with the known sequence of jacalin indica tes close to 50% sequence identity. Artocarpin crystallizes in two for ms, both monoclinic P2(1), with one and two tetramic molecules, respec tively, in the asymmetric units of form I (a = 69.9, b = 73.7, c = 60. 6 Angstrom and beta = 95.1 degrees) and form II (a = 87.6, b = 72.2, c = 92.6 Angstrom and beta = 101.1 degrees). Both the crystal structure s have been solved by the molecular replacement method using the known structure of jacalin as the search model and ope of them partially re fined, confirming that the two lectins are indeed homologous.