A molecular basis for the endo-β1,3-glucanase activity of the thaumatin-like proteins from edible fruits

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• 作者：Menu-Bouaouiche ; Laurence ; Vriet ; Christelle ; Peumans ; Willy J. ; Barre ; Annick ; Van Damme ; Els J.M. ; et. al.
• 关键词：PR-5 proteins ; Thaumatin-like proteins ; Edible fruits ; Endo-β ; 1 ; 3-glucanase ; Antifungal activity ; Ban-TLP ; banana (Musa acuminata) thaumatin-like protein ; CD ; circular dichroism ; Mal-TLP ; apple (Malus domesticus) thaumatin-like protein ; Pru-TLP ; cherr
• 刊名：Biochimie
• 出版年：2003
• 出版时间：January - February, 2003
• 年：2003
• 卷：85
• 期：1-2
• 页码：123-131
• 全文大小：378 K

文摘

Fruit-specific thaumatin-like proteins were isolated from cherry, apple and banana, and their enzymatic and antifungal activities compared. Both the apple and cherry possess a moderate endo-β1,3-glucanase activity but are devoid of antifugal activity. In contrast, the banana thaumatin-like protein inhibits the in vitro hyphal growth of Verticillium albo-atrum but is virtually devoid of endo-β1,3-glucanase activity. Both structural and molecular modeling studies showed that all three thaumatin-like proteins possess an extended electronegatively charged cleft at their surface, which is believed to be a prerequisite for endo-β1,3-glucanase activity. Docking experiments showed that the positioning of linear (1,3)-β-D-glucans in the cleft of the apple and cherry proteins allows an interaction with the glutamic acid residues that are responsible for the hydrolytic cleavage of the glucan. Due to a different positioning in the cleft of the banana thaumatin-like protein, the linear β-glucans cannot properly interact with the catalytic glutamic acid residues and as a result the protein possesses no enzymatic activity. The possible function of the fruit-specific thaumatin-like proteins is discussed in view of the observed biological activities and structural features.