Pätsi Jukka, Kervinen Marko, Kytövuori Laura, Majamaa Kari, Hassinen Ilmo E
Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
Department of Ophthalmology and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, P.O. Box 5000, FIN-90014 Oulu, Finland.
Mitochondrion. 2015 May;22:23-30. doi: 10.1016/j.mito.2015.02.007. Epub 2015 Mar 5.
Effects of Complex I mutations were studied by modeling in NuoH, NuoJ or NuoK subunits of Escherichia coli NDH-1 by simultaneous optical monitoring of deamino-NADH oxidation and proton translocation and fitting to the data a model equation of transmembrane proton transport. A homolog of the ND1-E24 LHON/MELAS mutation caused 95% inhibition of d-NADH oxidation and proton translocation. The NuoJ-Y59F replacement decreased proton translocation. The NuoK-E72Q mutation lowered the enzyme activity, but proton pumping could be rescued by the double mutation NuoK-E72Q/I39D. Moving the NuoK-E72/E36 pair one helix turn towards the periplasm did not affect redox activity but decreased proton pumping.
通过对大肠杆菌NDH-1的NuoH、NuoJ或NuoK亚基进行建模，同时光学监测脱氨基-NADH氧化和质子转运，并将跨膜质子转运的模型方程拟合到数据中，研究了复合物I突变的影响。ND1-E24 LHON/MELAS突变的同源物导致d-NADH氧化和质子转运受到95%的抑制。NuoJ-Y59F替代降低了质子转运。NuoK-E72Q突变降低了酶活性，但双突变NuoK-E72Q/I39D可挽救质子泵功能。将NuoK-E72/E36对向周质方向移动一个螺旋圈不影响氧化还原活性，但降低了质子泵功能。
