SALT-SOLUBLE SEED GLOBULINS OF DICOTYLEDONOUS AND MONOCOTYLEDONOUS PLANTS II - STRUCTURAL CHARACTERIZATION

Structural characterization of 21 seed globulins from monocotyledonous and dicotyledonous plants revealed that they generally possessed low levels of alpha-helix and high levels of beta-sheet secondary structur e fractions. This finding suggested that the interior conformation of these globulins was very similar. In contrast to internal conformation s, tertiary conformations indicated that very distinct surface propert ies existed between these two globulin classes. It now appears that su rface properties are the most variable physico-chemical properties mea sured between globulins. Calorimetric analysis revealed thai both clas ses of globulins possessed temperatures of denaturation (Td) which wer e in the temperature range of 83.8 to 107.8 degrees C. Although dicoty ledonous seed globulins had more pronounced thermal transitions than t heir monocotyledonous counterparts, most endothermic transitions occur red as co-operative events indicating that the various domains present in these globulins were held together by interdependent structural do mains. These interdependent domains rendered the globulins stable to h igh temperatures and in connection with previous data (Marcone and Yad a, 1998), it was believed that both monocotyledonous and dicotyledonou s seed globulins share similar structural domains. (C) 1998 Elsevier S cience Ltd. All rights reserved.