Biochemical characterization and functional analysis of invertase Bmsuc1 from silkworm, Bombyx mori
Biochemical characterization and functional analysis of invertase Bmsuc1 from silkworm, Bombyx mori
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家蚕转化酶 Bmsuc1 的生化表征及功能分析。
DOI：
10.1016/j.ijbiomac.2017.10.118
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发表时间：
2018-02-01
影响因子：
8.2
通讯作者：
Zhao, Ping
中科院分区：
文献类型：
--
作者：
Guo, Peng-Chao;Wang, Qian;Zhao, Ping
转化酶（EC 3.2.1.26）属于糖苷水解酶家族32，催化蔗糖水解为果糖和葡萄糖。Bmsuc 1的最适水解pH为7.0-8.0，以蔗糖为底物的最适温度为50 ℃。圆二色光谱表明Bmsuc 1主要为β链结构。Bmsuc 1的热变性转变是一个协同过程，Tm、Δ H和Δ S分别为53.81 +/- 0.12 ℃、185.51 +/- 0.14 KJ/mol和0.56 +/- 0.01 KJ/（mol K）。此外，同源性建模和多序列比对表明，Bmsuc 1具有典型的β-螺旋桨折叠和一个保守的催化三联体，Asp（63）-Aps（181）-Glu（234），其位于底物结合口袋的底部。Bmsuc 1在丝腺中的转录和翻译水平均高水平表达。这些表达谱结合转化酶活性分析表明，Bmsuc 1可能作为一种消化酶，水解丝腺腔中的糖。总的来说，这些发现扩展到更好地了解Bmsuc 1的结构及其在丝腺中的功能。(C)2017由Elsevier B. V.出版
Invertase or beta-fructofuranosidase (EC 3.2.1.26) belongs to the glycoside hydrolase family 32, which catalyzes the hydrolysis of sucrose into fructose and glucose, Here, we report the biochemical and functional characterization of invertase Bmsuc1 from Bombyx mori. Bmsuc1 showed optimal hydrolysis at pH 7.0-8.0 and its optimum temperature is 50 degrees C using sucrose as substrate. Circular dichroism spectra indicated Bmsuc1 had a primarily beta-strand structure. The thermal denaturations transition of Bmsuc1 was a cooperative process with a Tm, Delta H, and Delta S of 53.81 +/- 0.12 degrees C, 185.51 +/- 0.14 KJ/mol and 0.56 +/- 0.01 KJ/(mol K), respectively. Moreover, homology modeling and multi-sequence alignment suggested that Bmsuc1 has a canonical beta-propeller fold and one conserved catalytic triad, Asp(63)-Aps(181)-Glu(234), which is located in the bottom of the substrate-binding pocket. Bmsuc1 was expressed at high levels in the silk gland at both the transcriptional and translational levels. These expression profiles combined with invertase activity analyses of Bmsuc1 suggested that it might function as a digestive enzyme to hydrolyze sugar in the silk gland lumen. Collectively, these findings expand towards a better understanding of the structure of Bmsuc1 and its function in the silk gland. (C) 2017 Published by Elsevier B.V.