The non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) of Sulfolobus solfataricus:: a key-enzyme of the semi-phosphorylative branch of the Entner-Doudoroff pathway
The non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) of Sulfolobus solfataricus:: a key-enzyme of the semi-phosphorylative branch of the Entner-Doudoroff pathway
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DOI：
10.1007/s00792-007-0082-1
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发表时间：
2008-01-01
期刊：
影响因子：
2.9
通讯作者：
Siebers, Bettina
中科院分区：
文献类型：
--
作者：
Ettema, Thijs J. G.;Ahmed, Hatim;Siebers, Bettina
葡萄球菌利用经典Entner-Doudoroff（艾德）途径的分支修饰进行糖降解。半磷酸化分支在甘油醛3-磷酸（GAP）水平与Emden-Meyerhof-Parnas途径的较低共同分流合并。在硫磺硫化叶菌中鉴定了两种不同的GAP转化酶-经典磷酸化GAP脱氢酶（GAPDH）和非磷酸化GAPDH（GAPN）。在Sulfolobales中，发现GAPN编码基因邻近于艾德基因簇，表明在半磷酸化艾德分支的调节中的功能。重组S. solfataricus揭示，与来自Thermoproteus tenax的充分表征的GAPN一样，S. Solfataricus表现出变构性质。然而，这两种酶在共底物特异性和调节微调方面显示出一些意想不到的差异，这似乎反映了对两种生物不同生活方式的适应。系统发育分析和数据库搜索表明，在极端嗜热的GAPN（和/或GAP氧化还原酶）支持先前提出的作用，GAPN代谢热适应的GAPN的首选分布。这项工作表明，GAPN在调节碳降解的重要作用，通过修改的EMP和分支的艾德途径在超嗜热菌。
Archaea utilize a branched modification of the classical Entner-Doudoroff (ED) pathway for sugar degradation. The semi-phosphorylative branch merges at the level of glyceraldehyde 3-phosphate (GAP) with the lower common shunt of the Emden-Meyerhof-Parnas pathway. In Sulfolobus solfataricus two different GAP converting enzymes-classical phosphorylating GAP dehydrogenase (GAPDH) and the non-phosphorylating GAPDH (GAPN)-were identified. In Sulfolobales the GAPN encoding gene is found adjacent to the ED gene cluster suggesting a function in the regulation of the semi-phosphorylative ED branch. The biochemical characterization of the recombinant GAPN of S. solfataricus revealed that-like the well-characterized GAPN from Thermoproteus tenax-the enzyme of S. solfataricus exhibits allosteric properties. However, both enzymes show some unexpected differences in co-substrate specificity as well as regulatory fine-tuning, which seem to reflect an adaptation to the different lifestyles of both organisms. Phylogenetic analyses and database searches in Archaea indicated a preferred distribution of GAPN (and/or GAP oxidoreductase) in hyperthermophilic Archaea supporting the previously suggested role of GAPN in metabolic thermoadaptation. This work suggests an important role of GAPN in the regulation of carbon degradation via modifications of the EMP and the branched ED pathway in hyperthermophilic Archaea.