Crystal structure of a putative isochorismatase hydrolase from Oleispira antarctica.
Crystal structure of a putative isochorismatase hydrolase from Oleispira antarctica.
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DOI：
10.1007/s10969-012-9127-5
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发表时间：
2012-03
期刊：
影响因子：
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通讯作者：
Minor, Wladek
中科院分区：
文献类型：
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作者：
Goral, Anna M;Tkaczuk, Karolina L;Chruszcz, Maksymilian;Kagan, Olga;Savchenko, Alexei;Minor, Wladek
异分支酶样水解酶（Isochorismatase-like hydrolases，IHL）是一类酶，根据SCOP分为五个结构家族。IHL对于铁载体介导的细胞三价铁获取至关重要。这些分子的结构特征的知识将提高铁运输的分子基础的理解，并可能解决以前在文献中提出的机制是正确的。我们确定了一个假定的异分支酶水解酶OaIHL（PDB代码：3LQY）的脱辅基形式的晶体结构，从厌氧的γ-变形杆菌Oleispira anaitica，并进行比较序列和结构分析其最接近的同源物。所有分析的结构的特征进行了鉴定和讨论。我们还对接isochorismate的解决的晶体结构，通过计算机模拟的方法，突出的活性中心与基板的相互作用。假定的异分支酸水解酶OaIHL从Oleispira anaitica具有典型的催化三联体的IHL蛋白。其活性中心类似于具有D-K-C催化三联体的IHL，而不是具有D-K-X三联体的变体。OaIHL与国际人道主义法超家族的其他成员有一些共同的结构和顺序特征。计算机对接结果显示，尽管活性位点组成存在微小差异，但异分支酸酯以与其在吩嗪生物合成蛋白PhzD（PDB代码1 NF 8）中的结合类似的模式结合在OaIHL的结构中。
Isochorismatase-like hydrolases (IHL) constitute a large family of enzymes divided into five structural families (by SCOP). IHLs are crucial for siderophore-mediated ferric iron acquisition by cells. Knowledge of the structural characteristics of these molecules will enhance the understanding of the molecular basis of iron transport, and perhaps resolve which of the mechanisms previously proposed in the literature is the correct one. We determined the crystal structure of the apo-form of a putative isochorismatase hydrolase OaIHL (PDB code: 3LQY) from the antarctic γ-proteobacterium Oleispira antarctica, and did comparative sequential and structural analysis of its closest homologs. The characteristic features of all analyzed structures were identified and discussed. We also docked isochorismate to the solved crystal structure by in silico methods, to highlight the interactions of the active center with the substrate. The putative isochorismate hydrolase OaIHL from Oleispira antarctica possesses the typical catalytic triad for IHL proteins. Its active center resembles those IHLs with a D-K-C catalytic triad, rather than those variants with a D-K-X triad. OaIHL shares some structural and sequential features with other members of the IHL superfamily. In silico docking results showed that despite small differences in active site composition, isochorismate binds to in the structure of OaIHL in a similar mode to its binding in phenazine biosynthesis protein PhzD (PDB code 1NF8).