Friedrich Thorsten, Hellwig Petra
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104 Freiburg, Germany.
Biochim Biophys Acta. 2010 Jun-Jul;1797(6-7):659-63. doi: 10.1016/j.bbabio.2010.03.002. Epub 2010 Mar 7.
The proton-pumping NADH:ubiquinone oxidoreductase couples the transfer of electrons from NADH to ubiquinone with the translocation of protons across the membrane. This process is suggested to be accompanied by conformational changes of the enzyme that may be monitored by redox-induced FT-IR difference spectroscopy. Signals observed in the amide I range are partially attributed to local rearrangements that occur as an electrostatic response to the redox reactions of the FeS clusters. In addition, conformational changes can be reported that depend on pH and at the same time can be perturbed by site-directed mutagenesis of residue E67 on subunit B (the bacterial homologue of the mitochondrial PSST subunit). This residue is located in the vicinity of the cluster N2. Re-evaluating these previous data we here discuss a mechanism, by which the redox reaction of N2 induces conformational changes possibly leading to proton translocation.
质子泵NADH：泛醌氧化还原酶将电子从NADH转移至泛醌的过程与质子跨膜转运相偶联。该过程被认为伴随着酶的构象变化，这种变化可通过氧化还原诱导的傅里叶变换红外差光谱进行监测。在酰胺I区域观察到的信号部分归因于作为对FeS簇氧化还原反应的静电响应而发生的局部重排。此外，还可报告依赖于pH的构象变化，同时该变化可被亚基B上的E67残基（线粒体PSST亚基的细菌同源物）的定点诱变所干扰。该残基位于簇N2附近。通过重新评估这些先前的数据，我们在此讨论一种机制，即N2的氧化还原反应诱导构象变化，可能导致质子转运。
