Ueda Shuhei, Nomoto Ryohei, Yoshida Ken-ichi, Osawa Ro
Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Rokko-dai 1-1, Nada-ku, Kobe 657-8501, Japan.
BMC Microbiol. 2014 Apr 7;14:87. doi: 10.1186/1471-2180-14-87.
Tannase (tannin acyl hydrolase, EC 3.1.1.20) specifically catalyzes the hydrolysis of the galloyl ester bonds in hydrolyzable tannins to release gallic acid. The enzyme was found not only in fungal species but also many bacterial species including Lactobacillus plantarum, L. paraplantarum, and L. pentosus. Recently, we identified and expressed a tannase gene of L. plantarum, tanLpl, to show remarkable differences to characterized fungal tannases. However, little is known about genes responsible for tannase activities of L. paraplantarum and L. pentosus. We here identify the tannase genes (i.e. tanLpa and tanLpe) of the above lactobacilli species, and describe their molecular diversity among the strains as well as enzymological difference between species inclusive of L. plantarum.
The genes encoding tannase, designated tanLpa and tanLpe, were cloned from Lactobacillus paraplantarum NSO120 and Lactobacillus pentosus 21A-3, which shared 88% and 72% amino acid identity with TanLpl, cloned from Lactobacillus plantarum ATCC 14917(T), respectively. These three enzymes could comprise a novel tannase subfamily of independent lineage, because no other tannases in the databases share significant sequence similarity with them. Each of tanLpl, tanLpa, and tanLpe was expressed in Bacillus subtilis RIK 1285 and recombinant enzymes were secreted and purified. The K(m) values of the enzymes on each galloyl ester were comparable; however, the k(cat)/K(m) values of TanLpa for EGCg, ECg, Cg, and GCg were markedly higher than those for TanLpl and TanLpe. Their enzymological properties were compared to reveal differences at least in substrate specificity.
Two tannase genes responsible for tannase activities of L. paraplantarum and L. pentosus were identified and characterized. TanLpl, TanLpa and TanLpe forming a phylogenetic cluster in the known bacterial tannase genes and had a limited diversity in each other. Their enzymological properties were compared to reveal differences at least in substrate specificity. This is the first comparative study of closely related bacterial tannases.
单宁酶（单宁酰基水解酶，EC 3.1.1.20）特异性催化可水解单宁中没食子酰酯键的水解以释放没食子酸。该酶不仅在真菌物种中被发现，在包括植物乳杆菌、副植物乳杆菌和戊糖乳杆菌在内的许多细菌物种中也有发现。最近，我们鉴定并表达了植物乳杆菌的单宁酶基因tanLpl，发现其与已表征的真菌单宁酶有显著差异。然而，关于副植物乳杆菌和戊糖乳杆菌中负责单宁酶活性的基因知之甚少。我们在此鉴定了上述乳杆菌物种的单宁酶基因（即tanLpa和tanLpe），并描述了它们在菌株间的分子多样性以及包括植物乳杆菌在内的不同物种间的酶学差异。
从副植物乳杆菌NSO120和戊糖乳杆菌21A - 3中克隆了编码单宁酶的基因，分别命名为tanLpa和tanLpe，它们与从植物乳杆菌ATCC 14917(T)克隆的TanLpl的氨基酸同一性分别为88%和72%。这三种酶可能构成一个独立谱系的新型单宁酶亚家族，因为数据库中没有其他单宁酶与它们有显著的序列相似性。tanLpl、tanLpa和tanLpe分别在枯草芽孢杆菌RIK 1285中表达，重组酶被分泌并纯化。这些酶对每种没食子酰酯的K(m)值相当；然而，TanLpa对表没食子儿茶素没食子酸酯（EGCg）、表儿茶素没食子酸酯（ECg）、儿茶素没食子酸酯（Cg）和没食子酸丙酯（GCg）的k(cat)/K(m)值明显高于TanLpl和TanLpe。比较了它们的酶学性质以揭示至少在底物特异性方面的差异。
鉴定并表征了负责副植物乳杆菌和戊糖乳杆菌单宁酶活性的两个单宁酶基因。TanLpl、TanLpa和TanLpe在已知的细菌单宁酶基因中形成一个系统发育簇，彼此间多样性有限。比较了它们的酶学性质以揭示至少在底物特异性方面的差异。这是首次对密切相关的细菌单宁酶进行的比较研究。
Zotero 插件