Duarte M, Finel M, Videira A
Instituto de Ciências Biomédicas de Abel Salazar, Porto, Portugal.
Biochim Biophys Acta. 1996 Jul 31;1275(3):151-3. doi: 10.1016/0005-2728(96)00033-3.
We have isolated cDNA clones encoding an iron-sulfur polypeptide subunit of the mitochondrial complex I of Neurospora crassa. The fungal cDNA library was screened by hybridisation with an heterologous probe from Paracoccus denitrificans. The DNA sequence of relevant isolates was determined and revealed an open reading frame encoding a precursor protein of 219 amino acid residues. The gene product is a ferredoxin-like protein that contains two cysteine-rich motives that may each bind a tetranuclear iron-sulfur cluster. The primary structure of the protein is highly homologous to the 23 kDa iron-sulfur subunit of complex I from bovine and P. denitrificans. Interestingly, an alanine residue within the second cluster-binding motif, which is conserved in complex I but replaced by tyrosine in similar chloroplast genes, is substituted for serine in N. crassa.
我们已经分离出了编码粗糙脉孢菌线粒体复合体I的一个铁硫多肽亚基的cDNA克隆。用来自反硝化副球菌的异源探针通过杂交筛选真菌cDNA文库。确定了相关分离株的DNA序列，发现一个开放阅读框，编码一个含219个氨基酸残基的前体蛋白。该基因产物是一种铁氧化还原蛋白样蛋白，含有两个富含半胱氨酸的基序，每个基序可能结合一个四核铁硫簇。该蛋白的一级结构与牛和反硝化副球菌复合体I的23 kDa铁硫亚基高度同源。有趣的是，在复合体I中保守但在类似叶绿体基因中被酪氨酸取代的第二个簇结合基序内的一个丙氨酸残基，在粗糙脉孢菌中被丝氨酸取代。
