Schenk-Gröninger R, Becker J, Brendel M
Institut für Mikrobiologie, Abtl Biologie für Mediziner, JW Goethe-Universität, Frankfurt/Main, Germany.
Biochimie. 1995;77(4):265-72. doi: 10.1016/0300-9084(96)88135-1.
The gene encoding dihydroorotase (DHOase) of Lactobacillus leichmannii, the third enzyme of the pyrimidine biosynthetic pathway (Genbank (EMBL) accession no X78999), was cloned by phenotypic complementation of an E coli pyrC deficient mutant after transformation with Lactobacillus leichmannii genomic library DNA. The open reading frame of the L leichmannii pyrC gene spans 1281 bp and codes for a 427 amino cid polypeptide with a calculated M(r) of 46,316 Da. Primer extension showed that the initiation site for transcription is 37 bp upstream of the putative start codon ATG and Northern blot analysis confirmed its independent transcription from the adjacent pyrB gene. Comparison of the deduced amino acid sequence of L leichmannii DHOase with sequences established for other organisms yielded 46.6% identity with the corresponding Bacillus subtilis enzyme. Highly conserved protein domains suggest importance for the enzyme's function.
通过用莱氏乳杆菌基因组文库DNA转化大肠杆菌pyrC缺陷型突变体，经表型互补克隆了莱氏乳杆菌编码二氢乳清酸酶（DHOase）的基因，该酶是嘧啶生物合成途径的第三种酶（基因库（EMBL）登录号X78999）。莱氏乳杆菌pyrC基因的开放阅读框跨度为1281 bp，编码一个427个氨基酸的多肽，计算分子量为46316 Da。引物延伸显示转录起始位点在推定的起始密码子ATG上游37 bp处，Northern印迹分析证实其与相邻的pyrB基因独立转录。将莱氏乳杆菌DHOase推导的氨基酸序列与其他生物体已确定的序列进行比较，与相应的枯草芽孢杆菌酶有46.6%的同一性。高度保守的蛋白质结构域表明该酶功能的重要性。
