Inhibition of membrane-bound electron transport of the methanogenic archaeon Methanosarcina mazei Go1 by diphenyleneiodonium
Inhibition of membrane-bound electron transport of the methanogenic archaeon Methanosarcina mazei Go1 by diphenyleneiodonium
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DOI：
10.1046/j.1432-1327.1999.00017.x
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发表时间：
1999-01-01
期刊：
影响因子：
--
通讯作者：
Deppenmeier, U
中科院分区：
文献类型：
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作者：
Brodersen, J;Bäumer, S;Deppenmeier, U
氯化二苯碘铵（DPI）对马氏甲烷八叠球菌Go 1的质子转运电子传递系统（F420 H2：异二硫键氧化还原酶和H-2：异二硫键氧化还原酶）有抑制作用，其IC 50值分别为20 nmol DPI.mg（-1）蛋白和45 nmol DPI. mg（-1）蛋白。这些影响是由于DPI与电子传递链的关键酶的复杂相互作用。发现F-420非还原性氢化酶、F420 H2脱氢酶和杂二硫还原酶催化的2羟基奋乃静依赖性反应受到抑制。有趣的是，H-2-依赖性甲基紫精还原和异二硫键还原甲基紫精催化的氢化酶和异二硫键还原酶存在于洗涤膜不受DPI，分别。细胞色素的氧化还原行为分析表明，DPI抑制了CoB-S-S-CoM依赖的细胞色素氧化还原和H-2依赖的细胞色素还原。膜结合和纯化的F420 H2脱氢酶被DPI抑制，无论甲基紫精+甲硝唑或2-羟基吩嗪被用作电子受体。2-羟基-吩嗪依赖性F420 H2-氧化的详细检查显示DPI是酶的竞争性抑制剂，由2-羟基吩嗪的K-m值表示，其在DPI存在下从35 μ M增加到100 μ M。由于DPI和吩嗪在其平面构型方面在结构上相似，我们假设抑制剂能够结合到吩嗪与电子传递系统的组分之间发生相互作用的位置。因此，从还原的2-羟基吩嗪到作为杂二硫还原酶的一部分的细胞色素b1和从H2到作为膜结合氢化酶的亚基的细胞色素b1的电子转移在DPI的存在下受到影响。在F420 H2脱氢酶的情况下，从FAD或从FeS中心到2-羟基吩嗪的电子传递被抑制。
The proton translocating electron transport systems (F420H2:heterodisulfide oxidoreductase and H-2:heterodisulfide oxidoreductase) of Methanosarcina mazei Go1 were inhibited by diphenyleneiodonium chloride (DPI) indicated by IC50 values of 20 nmol DPI.mg(-1) protein and 45 nmol DPI.mg(-1) protein, respectively. These effects are due to a complex interaction of DPI with key enzymes of the electron transport chains. It was found that 2 hydroxyphenazine-dependent reactions as catalyzed by F-420-nonreducing hydrogenase, F420H2 dehydrogenase and heterodisulfide reductase were inhibited. Interestingly, the H-2-dependent methylviologen reduction and the heterodisulfide reduction by reduced methylviologen as catalyzed by the hydrogenase and the heterodisulfide reductase present in washed membranes were unaffected by DPI, respectively. Analysis of the redox behavior of membrane-bound cytochromes indicated that DPI inhibited CoB-S-S-CoM-dependent oxidation of reduced cytochromes and H-2-dependent cytochrome reduction. Membrane-bound and purified F420H2 dehydrogenase were inhibited by DPI irrespectively whether methylviologen + metronidazole or 2-hydroxyphenazine were used as electron accepters. Detailed examination of 2-hydroxy-phenazine-dependent F420H2-oxidation revealed that DPI is a competitive inhibitor of the enzyme, indicated by the K-m value for 2-hydroxyphenazine, which increased from 35 mu M to 100 mu M in the presence of DPI. As DPI and phenazines are structurally similar with respect to their planar configuration we assume that the inhibitor is able to bind to positions where interaction between phenazines and components of the electron transport systems take place. Thus, electron transfer from reduced 2-hydroxyphenazine to cytochrome bl as part of the heterodisulfide reductase and from H2 to cytochrome bl as subunit of the membrane-bound hydrogenase is affected in the presence of DPI. In case of the F420H2 dehydrogenase electron transport from FAD or from FeS centers to 2-hydroxyphenazine is inhibited.