Identification of a novel subunit of respiratory complex I from Thermus thermophilus
Identification of a novel subunit of respiratory complex I from Thermus thermophilus
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DOI：
10.1021/bi0600998
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发表时间：
2006-04-11
期刊：
影响因子：
2.9
通讯作者：
Sazanov, LA
中科院分区：
文献类型：
--
作者：
Hinchliffe, P;Carroll, J;Sazanov, LA
从嗜热生物Thermus thermophilus HB8中纯化并表征了质子易位NADH：醌氧化还原酶（复合物1）的亲水结构域（外周臂）。该亚络合物在十二烷基硫酸钠中稳定到80℃。在9个铁硫簇中，EPR可以在nadh还原酶中检测到4到5个（1或2个双核和3个四核）。该制剂由八种不同的多肽组成。其中7个已通过肽质量定位和n端测序确定为已知的嗜热T复合物i的亲水亚基。第8个多肽在所有阶段都与亚复合物共化，与其他亚基密切相关，并且存在于亚复合物的晶体中，用于x射线数据收集。因此，它被鉴定为一种新的配合物I亚基，并命名为Nqo15。它编码在一个与nqo操纵子分离的位点上，包含其他14个已知的复合体I基因。ORF编码的Nqo15同源物存在于嗜热T菌的近亲基因组中。我们的数据表明，与之前的假设相反，细菌复合体I除了包含14个亚基的“核心”补体外，还可以包含蛋白质。
The hydrophilic domain (peripheral arm) of the proton-translocating NADH:quinone oxidoreductase (complex 1) from the thermophilic organism Thermus thermophilus HB8 has been purified and characterized. The subcomplex is stable in sodium dodecyl sulfate up to 80 degrees C. Of nine iron-sulfur clusters, four to five (one or two binuclear and three tetranuclear) could be detected by EPR in the NADH-reduced enzyme. The preparation consists of eight different polypeptides. Seven of them have been positively identified by peptide mass mapping and N-terminal sequencing as known hydrophilic subunits of T thermophilus complex I. The eighth polypeptide copurified with the subcomplex at all stages, is strongly associated with the other Subunits, and is present in crystals of the subcomplex, used for X-ray data collection. Therefore, it has been identified as a novel complex I subunit and named Nqo15. It is encoded in a locus separate from the nqo operon, containing the 14 other known complex I genes. ORF's encoding Nqo15 homologues are present in the genomes of the closest relatives of T thermophilus. Our data show that, contrary to previous assumptions, bacterial complex I can contain proteins in addition to a "core" complement of 14 subunits.