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.

译文

:Archaea利用经典的Entner-Doudoroff(ED)途径的分支修饰来降解糖。半磷酸化分支在3-磷酸甘油醛(GAP)的水平与Emden-Meyerhof-Parnas途径的较低分流合并。在Sulfolobus solfataricus中,确定了两种不同的GAP转化酶,即经典的磷酸化GAP脱氢酶(GAPDH)和非磷酸化的GAPDH(GAPN)。在Sulfolobales中,发现GAPN编码基因与ED基因簇相邻,提示其在调节半磷酸化ED分支中起作用。鼠李糖链球菌重组GAPN的生化特性表明,就像来自嗜热变形菌的特征充分的GAPN一样,鼠李糖链球菌的酶表现出变构特性。但是,这两种酶在共底物特异性和调节性微调方面均表现出一些出乎意料的差异,这似乎反映了对两种生物体不同生活方式的适应。在古生菌中的系统发育分析和数据库搜索表明,超嗜热古生菌中GAPN(和/或GAP氧化还原酶)的优选分布,支持了GAPN在代谢热适应中的先前建议作用。这项工作表明,GAPN在超嗜热古生菌中通过修饰EMP和分支ED途径在碳降解调节中起着重要作用。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录