牛樟芝內切型纖維水解酵素之分子特性

牛樟芝為臺灣重要的褐腐真菌，已經被證實具有多樣且重要的天然化合物，使其具有龐大的醫藥潛能，由於牛樟芝只特定生長於牛樟的樹穴中，人工培養難以獲得等量之特殊化合物以致牛樟芝價格高昂，改善人工培養條件一直為努力的目標。纖維水解酵素為真菌生長所必需之重要酵素之一，前人研究發現從人工培養之菌絲體基因資料庫中獲得一段大量表現的內切型纖維水解酵素基因的序列片段，本實驗再利用Rapid Amplification of cDNA Ends（RACE）技術完成該片段之基因全長，總共獲得1,367個鹼基對的基因全長，而此基因全長包含了1,002個鹼基對的可轉譯區塊，經預測可生成含有共333個胺基酸之蛋白質，預測大小為35.8 kDa，並預測該基因所轉譯之蛋白質具有22個胺基酸的訊息片段，經資料庫比對推測該基因所產生之蛋白為負責水解纖維素的內切型纖維水解酵素（β-1,4-endoglucanase），並將該基因取名為AcEG1，同時也完成該基因之親緣演化關係圖確定其分類地位及蛋白質結構圖藉以觀察蛋白質與其糖類基質的作用關係，希望藉由了解該酵素之特性為往後牛樟芝人工培養及生化應用提供基礎之參考資料。

關鍵字

牛樟芝；纖維素；纖維水解酵素；蛋白質結構

並列摘要

＂Antrodia cinnamomea＂, a valuable brown-rot fungus in Taiwan, has diverse bioactive compounds with large pharmaceutical potentials. ＂A. cinnamomea＂ can only be found in inner cavity of Cinnamomum kanehirae Hayata. It is difficult to obtain certain metabolites under artificial culture environment; thus, causing ＂A. cinnamomea＂ to be expensive. Cellulase is one of the most important enzymes in basic metabolism of fungus growth. In artificial-cultured-mycelium gene library, we found a highly expressed DNA fragment, which can encode the cellulose, β-1,4-endoglucanase. We completed the full length of this DNA fragment with 5' and 3' RACE technique. This gene contains 1,367 base pairs (bp) in full length, which consists of 1,002 bp in the coding sequence that can generate 333 amino acids with 35.8 kDa predicted molecular weight, and the translated protein contains 22 amino acids as signal peptide. According to functional prediction in the Genbank database, we predicted this sequence to be β-1,4-endoglucanase, which participates in cellulose hydrolysis, and we named it as ＂AcEG1＂. We set up the phylogenetic tree and homology protein structure of ＂AcEG1＂. This information can act as reference for improving the culture methods and further biochemical applications.

並列關鍵字

Antrodia cinnamomea ； cellulose ； cellulose ； homology protein structure

國際替代計量

牛樟芝內切型纖維水解酵素之分子特性

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