The structural and mutational analyses of O-ureido-L-serine synthase necessary for D-cycloserine biosynthesis
The structural and mutational analyses of O-ureido-L-serine synthase necessary for D-cycloserine biosynthesis
复制标题
D-环丝氨酸生物合成所需的O-脲基-L-丝氨酸合酶的结构和突变分析
DOI：
10.1111/febs.13386
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Sugiyama M.
中科院分区：
文献类型：
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作者：
Uda N;Matoba Y;Oda K;Kumagai T;Sugiyama M.
我们最近成功地从生产 d-CS 的淡紫色链霉菌 ATCC11924 中克隆了生物合成 d-CS 所需的基因簇。尽管dcsD是位于基因簇上的ORF之一，编码与O-乙酰丝氨酸硫化氢解酶同源的蛋白质，该酶使用O-乙酰基-L-丝氨酸与硫化物合成l-半胱氨酸，但它的功能是使用O-乙酰基-L-丝氨酸与羟基脲（HU）一起形成O-脲基-L-丝氨酸作为ad-CS生物合成中间体。在本研究中，通过晶体学和突变研究，确定了 DcsD 中对 HU 底物偏好很重要的三个氨基酸残基。我们发现三个残基中的两个对于 HU 结合到底物结合袋中很重要。另一个残基有助于在催化反应过程中形成松散的氢键网络。有关氨基酸残基的信息对于设计用于合成β-取代-L-丙氨酸衍生物的新催化剂将非常有用。数据库野生型DcsD和DcsD的l-OUS结合的K43A突变体的原子坐标和结构因子已分别以登录码3X43和3X44存放在蛋白质数据库中。
We have recently been successful in cloning a gene cluster necessary for the biosynthesis ofd‐cycloserine (d‐CS) fromd‐CS‐producingStreptomyces lavendulaeATCC11924. AlthoughdcsD, one of the ORFs located on the gene cluster, encodes a protein homologous toO‐acetylserine sulfhydrylase that synthesizesl‐cysteine usingO‐acetyl‐l‐serine together with sulfide, it functions to formO‐ureido‐l‐serine as ad‐CS biosynthetic intermediate, usingO‐acetyl‐l‐serine together with hydroxyurea (HU). In the present study, using crystallographic and mutational studies, three amino acid residues in DcsD that are important for the substrate preference toward HU were determined. We showed that two of the three residues are important for the binding of HU into the substrate‐binding pocket. The other residue contributes to the formation of a loose hydrogen‐bond network during the catalytic reaction. Information regarding the amino acid residues will be very useful in the design of a new catalyst for synthesizing the β‐substituted‐l‐alanine derivatives.DatabaseThe atomic coordinates and structure factors of wild‐type DcsD andl‐OUS‐bound K43A mutant of DcsD have been deposited in the Protein Data Bank under accession codes 3X43 and 3X44, respectively.