Comparative analysis of β‐1,3‐glucanase protein sequences and structure in two banana cultivars from Kerala

The β‐1,3‐glucanase (E.C. 3.2.1.39) catalyzes the cleavage of 1,3‐β‐D‐glucosidic linkages in β‐1,3‐glucans. Hence the present study reported the analysis of β‐1,3‐glucanase protein from a fast ripening (Musa acuminata cv. Palayancodan) and delayed ripening (Musa acuminata cv. Kadali) banana cultivars from Kerala. Purified β‐1,3‐glucanase of Musa acuminata cv. Palayancodan consisted of 237 amino acids whereas in Musa acuminata cv. Kadali only 208 amino acids were present. Domain analysis and structural modeling of β‐1,3‐glucanase from these two cultivars also showed significant difference. Secondary structure of β‐1,3‐glucanase in cv. Kadali consisted of 9 α‐helices and 7 β‐strands but in cv. Palayancodan equal number of α‐helices (8) and β‐strands (8) are found. The secondary structure is more disordered (41 disorders) in cv. Kadali than in cv. Palayancodan (only 33 disorders). The present study provided useful insights into the structure of β‐1,3‐glucanase of two banana cultivars with different ripening properties. PRACTICAL APPLICATIONS: In banana fruit softening is the most important determinant of ripening process and delay in ripening has great significance in global market since the fruit is commercially important. Palayancodan, is a fast ripening banana cultivar and β‐1,3‐glucanase protein from this banana cultivar showed maximum number of amino acids (237). Kadali is remarkable with its small fruits and in these fruits the ripening is very slow. The β‐1,3‐glucanase from Kadali, consisted of 208 amino acids, in this cultivar 29 amino acids fewer than fast ripening cultivar. Hence, present study is a comparative report on β‐1,3‐glucanase sequences and structure among two banana cultivars with varied ripening property. Fruit ripening is naturally delayed in Kadali due to the slow/gradual decrease in fruit firmness and the fruit did not spoil even after 10 days. The naturally delayed ripening process in Kadali has great significance in the bioengineering of ripening mechanism in banana.