Crystallization and preliminary crystallographic analysis of D-alanine-D-alanine ligase from Streptococcus mutans.
Crystallization and preliminary crystallographic analysis of D-alanine-D-alanine ligase from Streptococcus mutans.
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DOI：
10.1107/s1744309107040298
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发表时间：
2007-09
期刊：
影响因子：
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通讯作者：
Yongxian Lu;Y. Sheng;Lan-fen Li;De-Wei Tang;Xiang Liu;Xiaojun Zhao;Yu-He Liang;X. Su
中科院分区：
文献类型：
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作者：
Yongxian Lu;Y. Sheng;Lan-fen Li;De-Wei Tang;Xiang Liu;Xiaojun Zhao;Yu-He Liang;X. Su
D-丙氨酸-D-丙氨酸连接酶由变形链球菌中的基因ddl（SMU_599）编码。这种连接酶在细胞壁生物合成中起着非常重要的作用，并可能成为药物设计的潜在靶点。为了研究该连接酶的结构和功能，从S.将其克隆到表达载体pET 28 a中。该蛋白在大肠杆菌BL 21（DE 3）中以可溶性形式表达。使用由Ni 2 +-螯合和尺寸排阻色谱组成的两步程序获得均一蛋白。使纯化的蛋白质结晶，立方晶体衍射至2.4埃。晶体属P3（1）21或P3（2）21空间群，晶胞参数a = B = 79.50，c = 108.97 A。每个不对称单元有一个分子。
D-Alanine-D-alanine ligase is encoded by the gene ddl (SMU_599) in Streptococcus mutans. This ligase plays a very important role in cell-wall biosynthesis and may be a potential target for drug design. To study the structure and function of this ligase, the gene ddl was amplified from S. mutans genomic DNA and cloned into the expression vector pET28a. The protein was expressed in soluble form in Escherichia coli strain BL21 (DE3). Homogeneous protein was obtained using a two-step procedure consisting of Ni2+-chelating and size-exclusion chromatography. Purified protein was crystallized and the cube-shaped crystal diffracted to 2.4 A. The crystal belongs to space group P3(1)21 or P3(2)21, with unit-cell parameters a = b = 79.50, c = 108.97 A. There is one molecule per asymmetric unit.