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 structure fractions. This finding suggested that the interior conformation of these globulins was very similar. In contrast to internal conformations, tertiary conformations indicated that very distinct surface properties existed between these two globulin classes. It now appears that surface properties are the most variable physico-chemical properties measured between globulins. Calorimetric analysis revealed thai both classes of globulins possessed temperatures of denaturation (Td) which were in the temperature range of 83.8 to 107.8 degrees C. Although dicotyledonous seed globulins had more pronounced thermal transitions than their monocotyledonous counterparts, most endothermic transitions occurred as co-operative events indicating that the various domains present in these globulins were held together by interdependent structural domains. These interdependent domains rendered the globulins stable to high temperatures and in connection with previous data (Marcone and Yada, 1998), it was believed that both monocotyledonous and dicotyledonous seed globulins share similar structural domains. (C) 1998 Elsevier Science Ltd. All rights reserved.