Brown T A, Davies R W, Ray J A, Waring R B, Scazzocchio C
Department of Biochemistry, University of Manchester Institute of Science and Technology, UK.
EMBO J. 1983;2(3):427-35. doi: 10.1002/j.1460-2075.1983.tb01440.x.
A 2830-bp segment of the mitochondrial genome of the fungus Aspergillus nidulans was sequenced and shown to contain two unidentified reading frames (URFs). These reading frames are 352 and 488 codons in length, and would specify unmodified proteins of mol. wts. 39,000 and 54,000, respectively. The derived amino acid sequences indicate that these genes are equivalent to the human mitochondrial URFs 1 and 4, with 39% amino acid homology for URF1 and 26% for URF4. Both URFs were shown by secondary structure predictions to code for predominantly beta-sheeted proteins with strong structural conservation between the fungal and human homologues. Counterparts of mammalian URFs have not previously been identified in non-mammalian genomes, and the discovery that A. nidulans possesses reading frames so closely homologous with URF1 and URF4 shows that these genes are of general functional importance in the mitochondria of diverse species.
对构巢曲霉线粒体基因组的一段2830 bp片段进行了测序，结果显示其包含两个未鉴定的阅读框（URF）。这些阅读框长度分别为352和488个密码子，分别编码分子量为39,000和54,000的未修饰蛋白质。推导的氨基酸序列表明，这些基因分别等同于人类线粒体URF1和URF4，URF1的氨基酸同源性为39%，URF4为26%。二级结构预测表明，这两个URF编码的主要是β折叠蛋白，真菌和人类同源物之间具有很强的结构保守性。此前在非哺乳动物基因组中尚未鉴定出哺乳动物URF的对应物，构巢曲霉拥有与URF1和URF4如此紧密同源的阅读框这一发现表明，这些基因在不同物种的线粒体中具有普遍的功能重要性。
