Kapoor M, Vijayaraghavan Y, Kadonaga R, LaRue K E
Department of Biological Sciences, University of Calgary, Alta., Canada.
Biochem Cell Biol. 1993 Mar-Apr;71(3-4):205-19. doi: 10.1139/o93-032.
The NAD(+)-specific glutamate dehydrogenase (NAD-GDH) of the filamentous fungus Neurospora crassa is a tetrameric enzyme, regulated by catabolite repression. The amino acid sequence of this enzyme had been published several years ago. With the object of investigating the molecular mechanism of catabolite repression, the nucleotide sequence of genomic clones containing the coding region, along with 5'- and 3'-flanking noncoding segments of the NAD-GDH transcription unit, was obtained. The gdh structural gene was shown to code for a polypeptide of 1047 residues, with a calculated molecular mass of 118,280 daltons. The coding sequence is interrupted by two short introns located close to the N- and C-terminal domains of the polypeptide. Consensus intron boundaries and internal splice sequences resemble closely those of other N. crassa genes. A comparison of the amino acid sequence deduced from the nucleotide sequence with the previously published sequence showed several discrepancies between the two. Nucleotide sequence corresponding to a gap in the amino acid sequence was located in the genomic clone. Genetic mapping by restriction fragment length polymorphism analysis localized the gdh gene close to the loci trp-1 and con-7 on the right arm of linkage group III.
丝状真菌粗糙脉孢菌的NAD(+)特异性谷氨酸脱氢酶（NAD-GDH）是一种受分解代谢物阻遏调控的四聚体酶。该酶的氨基酸序列已于数年前发表。为了研究分解代谢物阻遏的分子机制，获得了包含编码区以及NAD-GDH转录单元5'和3'侧翼非编码片段的基因组克隆的核苷酸序列。gdh结构基因编码一个由1047个残基组成的多肽，计算分子量为118,280道尔顿。编码序列被两个短内含子打断，这两个内含子靠近多肽的N端和C端结构域。内含子边界和内部剪接序列的共有序列与粗糙脉孢菌的其他基因非常相似。将核苷酸序列推导的氨基酸序列与先前发表的序列进行比较，发现两者之间存在一些差异。在基因组克隆中定位到了与氨基酸序列中的一个缺口相对应的核苷酸序列。通过限制性片段长度多态性分析进行的遗传图谱定位表明，gdh基因位于连锁群III右臂上靠近trp-1和con-7位点的位置。
