Prediction and comparison of the secondary structure of legume lectins

Secondary structure prediction for the 4 legume lectins: Concanavalin A, soybean agglutinin, favabean lectin and lentil lectin, was done by the method of Chou and Fasman. This prediction shows that these four lectins fall into a structurally distinct class of proteins, containing high amounts of β-sheet and β-turns. There is a notable similarity in the gross structure of these proteins; all four of them contain about 40-50% of β-sheet, 35-45 % β-turn and 0-10% of α-helix. When the secondary structure of corresponding residues in each pair of these lectins was compared, there was a striking similarity in the Concanavalin A-soybean agglutinin and favabean lectin-lentil lectin pairs, and considerably less similarity in the other pairs, suggesting that these legume lectins have probably evolved in a divergent manner from a common ancestor. A comparison of the predicted potential β-turn sites also supports the hypothesis of divergent evolution in this class of lectins

A new scalarane sesterterpene from a marine sponge Hyatella cribrifomis Hyatt of the Indian ocean

325-328A new scalarane sesterterpene, 24-β-methoxyscalarolide 4, along with known scalaranes- 12-epi-deoxoscalarin 1, 12-epi-12-deacetyl-25-deoxyscalarin 2 and scalarolide 3 has been isolated from a marine sponge, Hyatella cribriformis, of the Indian ocean. The structure of compound 4 has been determined on the basis of ¹H and ¹³C NMR, DEPT, ¹H-¹H COSY and EIMS experiments