F1F0-ATP synthases of alkaliphilic bacteria: lessons from their adaptations.
F1F0-ATP synthases of alkaliphilic bacteria: lessons from their adaptations.
复制标题
DOI：
10.1016/j.bbabio.2010.02.028
复制
发表时间：
2010-08
期刊：
影响因子：
--
通讯作者：
Krulwich TA
中科院分区：
文献类型：
--
作者：
Hicks DB;Liu J;Fujisawa M;Krulwich TA
本文综述了嗜碱细菌的ATP合成酶，特别是那些成功克服了在外部pH值> 10时实现强大的H+偶联ATP合成的生物能量挑战的ATP合成酶。在这样的pH值下，质子动力（其被假定为提供ATP合成的能量驱动力）太低而不能解释所观察到的ATP合成。质子动力在非常高的pH下由于需要维持细胞质pH远低于外部pH而降低，这导致能量上不利的pH梯度。这个生物能难题的几个预期的解决方案已经被排除在外。虽然在碱性条件下跨膜钠动力高，但呼吸性嗜碱细菌不使用Na+-而不是H+-偶联的ATP酶。它们也不抵消不利的pH梯度与质子动力的跨膜电位分量的补偿性增加。此外，ATP合成酶转子的研究表明，嗜碱菌不能完全解决的能量问题，通过使用一个ATP合成酶与大量的C-亚基的合成酶转子环。现在越来越多的注意力集中在膜表面附近的离域梯度和H+通过H+泵复合物和ATP酶之间的膜相关微电路转移到ATP酶。微电路可能取决于泵和酶的接近程度、特定的膜性质和参与酶复合物的特定适应性。嗜碱菌的ATP合成依赖于ATP合酶的嗜碱特异性适应，也有证据表明呼吸链组分的嗜碱特异性适应。
This review focuses on the ATP synthases of alkaliphilic bacteria and, in particular, those that successfully overcome the bioenergetic challenges of achieving robust H+-coupled ATP synthesis at external pH values > 10. At such pH values the protonmotive force, which is posited to provide the energetic driving force for ATP synthesis, is too low to account for the ATP synthesis observed. The protonmotive force is lowered at very high pH by the need to maintain a cytoplasmic pH well below the pH outside, which results in an energetically adverse pH gradient. Several anticipated solutions to this bioenergetic conundrum have been ruled out. Although the transmembrane sodium motive force is high under alkaline conditions, respiratory alkaliphilic bacteria do not use Na+-instead of H+-coupled ATP synthases. Nor do they offset the adverse pH gradient with a compensatory increase in the transmembrane electrical potential component of the protonmotive force. Moreover, studies of ATP synthase rotors indicate that alkaliphiles cannot fully resolve the energetic problem by using an ATP synthase with a large number of c-subunits in the synthase rotor ring. Increased attention now focuses on delocalized gradients near the membrane surface and H+ transfers to ATP synthases via membrane-associated microcircuits between the H+ pumping complexes and synthases. Microcircuits likely depend upon proximity of pumps and synthases, specific membrane properties and specific adaptations of the participating enzyme complexes. ATP synthesis in alkaliphiles depends upon alkaliphile-specific adaptations of the ATP synthase and there is also evidence for alkaliphile-specific adaptations of respiratory chain components.
登录
查看更多内容
影响因子：
4.4
作者：
Chi, Sulene L.;Pizzo, Salvatore V.
通讯作者：
Pizzo, Salvatore V.
影响因子：
4.8
作者：
Claggett, Shane B.;Plancher, Mac O'Neil;Cain, Brian D.
通讯作者：
Cain, Brian D.
DOI：
10.1073/pnas.92.2.372
发表时间：
1995-01-17
影响因子：
11.1
作者：
ALEXIEV, U;MOLLAAGHABABA, R;HEYN, MP
通讯作者：
HEYN, MP
影响因子：
56.9
作者：
Andries, K;Verhasselt, P;Jarlier, V
通讯作者：
Jarlier, V
影响因子：
4.8
作者：
Angevine, CM;Fillingame, RH
通讯作者：
Fillingame, RH