Elimination of Rubisco alters the regulation of nitrogenase activity and increases hydrogen production in Rhodospirillum rubrum.
Elimination of Rubisco alters the regulation of nitrogenase activity and increases hydrogen production in Rhodospirillum rubrum.
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DOI：
10.1016/j.ijhydene.2010.04.183
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发表时间：
2010-07-01
影响因子：
7.2
通讯作者：
Roberts, Gary P.
中科院分区：
文献类型：
--
作者：
Wang, Di;Zhang, Yaoping;Welch, Emily;Li, Jilun;Roberts, Gary P.
固氮酶不仅将大气中的氮还原为氨，还将质子还原为氢（H2）。固氮酶系统是许多光合细菌在光合和氮限制条件下产生H2的主要手段，包括红色红球藻。这种生物H2生产的效率在很大程度上取决于固氮酶以及细胞中ATP和电子的可用性。以往的研究表明，阻断R.红色诱导固氮酶活性，即使在铵的存在下，大概是为了去除细胞中过量的还原剂。我们在这里报告的cbbM突变体在R。研究Rubisco对H2产生的影响。我们新构建的cbbM突变体在厌氧条件下在苹果酸盐培养基中生长不良。然而，引入组成型活性NifA（NifA*），固氮（nif）基因的转录激活因子，允许cbbM突变体通过固氮酶系统消散过量的还原剂并改善其生长。有趣的是，我们发现cbbM的缺失改变了固氮酶活性的翻译后调节，导致在铵存在下部分活性固氮酶。nifA、draT和cbbM突变的组合大大增加了R.红色，特别是在存在过量铵的情况下。此外，这些突变体能够在比野生型长得多的时间范围内产生H2，增加了这些重组菌株用于生物生产H2的潜力。
Nitrogenase not only reduces atmospheric nitrogen to ammonia, but also reduces protons to hydrogen (H2). The nitrogenase system is the primary means of H2 production under photosynthetic and nitrogen-limiting conditions in many photosynthetic bacteria, including Rhodospirillum rubrum. The efficiency of this biological H2 production largely depends on the nitrogenase enzyme and the availability of ATP and electrons in the cell. Previous studies showed that blockage of the CO2 fixation pathway in R. rubrum induced nitrogenase activity even in the presence of ammonium, presumably to remove excess reductant in the cell. We report here the re-characterization of cbbM mutants in R. rubrum to study the effect of Rubisco on H2 production. Our newly constructed cbbM mutants grew poorly in malate medium under anaerobic conditions. However, the introduction of constitutively active NifA (NifA*), the transcriptional activator of the nitrogen fixation (nif) genes, allows cbbM mutants to dissipate the excess reductant through the nitrogenase system and improves their growth. Interestingly, we found that the deletion of cbbM alters the posttranslational regulation of nitrogenase activity, resulting in partially active nitrogenase in the presence of ammonium. The combination of mutations in nifA, draT and cbbM greatly increased H2 production of R. rubrum, especially in the presence of excess of ammonium. Furthermore, these mutants are able to produce H2 over a much longer time frame than the wild type, increasing the potential of these recombinant strains for the biological production of H2.
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影响因子：
7.2
作者：
Jamil, Zadariana;Annuar, Mohamad Suffian Mohamad;Vikineswary, S.
通讯作者：
Vikineswary, S.
影响因子：
3.2
作者：
GORRELL, TE;UFFEN, RL
通讯作者：
UFFEN, RL
影响因子：
7.2
作者：
Kim, Eui-Jin;Lee, Moon-Kyu;Lee, Jeong K.
通讯作者：
Lee, Jeong K.
影响因子：
7.2
作者：
Kim, Eui-Jin;Kim, Mi-Sun;Lee, Jeong K.
通讯作者：
Lee, Jeong K.
影响因子：
7.2
作者：
Kim, EJ;Kim, JS;Lee, JK
通讯作者：
Lee, JK