Zagorec M, Buhler J M, Treich I, Keng T, Guarente L, Labbe-Bois R
Laboratoire de Biochimie des Porphyrines, Institut Jacques Monod, University Paris VII, France.
J Biol Chem. 1988 Jul 15;263(20):9718-24.
The HEM13 gene of Saccharomyces cerevisiae codes for coproporphyrinogen oxidase (EC 1.3.3.3) catalyzing the sixth enzymic step in the heme biosynthetic pathway. Its expression has been previously shown to be regulated negatively by heme and oxygen. We have isolated the HEM13 gene by functional complementation of a hem13 gene by functional complementation of a hem13 mutant and determined its nucleotide sequence. The open reading frame encodes a protein of 328 amino acids. Its calculated molecular weight (37,673), amino acid composition and amino-terminal sequence predicted from the DNA sequence are in agreement with those determined for the native enzyme (Camadro, J. M., Chambon, H., Jolles, J., and Labbe, P. (1986) Eur. J. Biochem. 156, 579-587). The 5' ends of the HEM13 transcripts were identified by nuclease S1 mapping; induction of HEM13 resulted in an equivalent increase of the level of all the transcripts. 5' deletion analysis revealed that DNA sequence located upstream of 409 nucleotides from the translational initiation codon was needed for depression under oxygen limitation. The loss of induction of coproporphyrinogen oxidase activity by anaerobiosis caused a considerable decrease of heme formation in anaerobic cells.
酿酒酵母的HEM13基因编码粪卟啉原氧化酶（EC 1.3.3.3），该酶催化血红素生物合成途径中的第六步酶促反应。此前已表明其表达受血红素和氧气的负调控。我们通过对hem13突变体进行功能互补，分离出了HEM13基因，并测定了其核苷酸序列。开放阅读框编码一个由328个氨基酸组成的蛋白质。根据DNA序列预测的其计算分子量（37,673）、氨基酸组成和氨基末端序列与天然酶的测定结果一致（卡马德罗，J.M.，尚邦，H.，若尔，J.，和拉贝，P.（1986年）《欧洲生物化学杂志》156，579 - 587）。通过核酸酶S1图谱鉴定了HEM13转录本的5'末端；HEM13的诱导导致所有转录本水平同等增加。5'缺失分析表明，在氧气限制条件下抑制作用需要位于翻译起始密码子上游409个核苷酸处的DNA序列。厌氧状态下粪卟啉原氧化酶活性诱导的丧失导致厌氧细胞中血红素形成显著减少。
