کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8298592 | 1537034 | 2018 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Identification and characterization two isoforms of NADH:ubiquinone oxidoreductase from the hyperthermophilic eubacterium Aquifex aeolicus
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش گیاه شناسی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
The NADH:ubiquinone oxidoreductase (complex I) is the first enzyme of the respiratory chain and the entry point for most electrons. Generally, the bacterial complex I consists of 14 core subunits, homologues of which are also found in complex I of mitochondria. In complex I preparations from the hyperthermophilic bacterium Aquifex aeolicus we have identified 20 partially homologous subunits by combining MALDI-TOF and LILBID mass spectrometry methods. The subunits could be assigned to two different complex I isoforms, named NQOR1 and NQOR2. NQOR1 consists of subunits NuoA2, NuoB, NuoD2, NuoE, NuoF, NuoG, NuoI1, NuoH1, NuoJ1, NuoK1, NuoL1, NuoM1 and NuoN1, with an entire mass of 504.17â¯kDa. NQOR2 comprises subunits NuoA1, NuoB, NuoD1, NuoE, NuoF, NuoG, NuoH2, NuoI2, NuoJ1, NuoK1, NuoL2, NuoM2 and NuoN2, with a total mass of 523.99â¯kDa. Three Fe-S clusters could be identified by EPR spectroscopy in a preparation containing predominantly NQOR1. These were tentatively assigned to a binuclear center N1, and two tetranuclear centers, N2 and N4. The redox midpoint potentials of N1 and N2 are â273â¯mV and â184â¯mV, respectively. Specific activity assays indicated that NQOR1 from cells grown under low concentrations of oxygen was the more active form. Increasing the concentration of oxygen in the bacterial cultures induced formation of NQOR2 showing the lower specific activity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1859, Issue 5, May 2018, Pages 366-373
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1859, Issue 5, May 2018, Pages 366-373
نویسندگان
Guohong Peng, Björn Meyer, Lucie Sokolova, Wenxia Liu, Sandra Bornemann, Jana Juli, Klaus Zwicker, Michael Karas, Bernd Brutschy, Hartmut Michel,