Genetic analysis of coenzyme A biosynthesis in the yeast Saccharomyces cerevisiae: identification of a conditional mutation in the pantothenate kinase gene CAB1
Genetic analysis of coenzyme A biosynthesis in the yeast Saccharomyces cerevisiae: identification of a conditional mutation in the pantothenate kinase gene CAB1
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DOI：
10.1007/s00294-009-0234-1
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发表时间：
2009-04-01
期刊：
影响因子：
2.5
通讯作者：
Schueller, Hans-Joachim
中科院分区：
文献类型：
--
作者：
Olzhausen, Judith;Schuebbe, Sabrina;Schueller, Hans-Joachim
辅酶A（Coenzyme A，CoA）是一种广泛存在的辅因子，参与多种酶促碳基转移反应。辅酶A的生物合成需要各种氨基酸的贡献，其中泛酸是一种重要的中间体，可以从培养基中输入或从头合成。通过对酿酒酵母中CoA生物合成相关结构基因的功能和表达的研究，发现缺失ECM 31和PAN 6会导致泛酸突变体，而缺失PAN 5（与来自E.大肠杆菌）仍然允许原养型生长。脂肪酸合成酶活性缺陷的温度敏感突变体可以通过与真核泛酸激酶（YDR 531 W）显著相似的基因进行功能互补。通过细菌和哺乳动物基因对该突变进行的酶促研究和异源互补表明，YDR 531 W编码真正的泛酸激酶（新基因名称：CAB 1，“辅酶A生物合成”）。CAB1内的G351S错义突变被鉴定为引起最初研究的突变体的条件表型。与CAB 1相似，负责晚期CoA生物合成的基因YIL 083C、YKL 088W、YGR 277C和YDR 106C被证明是必需的。coaBC、coaD和coaE可以分别与coaBC、coaD和coaE互补。比较表达分析表明，与葡萄糖相比，乙醇作为碳源时，一些CoA生物合成基因的去阻遏作用较弱。
Coenzyme A (CoA) is a ubiquitous cofactor required for numerous enzymatic carbon group transfer reactions. CoA biosynthesis requires contributions from various amino acids with pantothenate as an important intermediate which can be imported from the medium or synthesized de novo. Investigating function and expression of structural genes involved in CoA biosynthesis of the yeast Saccharomyces cerevisiae, we show that deletion of ECM31 and PAN6 results in mutants requiring pantothenate while loss of PAN5 (related to panE from E. coli) still allows prototrophic growth. A temperature-sensitive mutant defective for fatty acid synthase activity could be functionally complemented by a gene significantly similar to eukaryotic pantothenate kinases (YDR531W). Enzymatic studies and heterologous complementation of this mutation by bacterial and mammalian genes showed that YDR531W encodes a genuine pantothenate kinase (new gene designation: CAB1, "coenzyme A biosynthesis"). A G351S missense mutation within CAB1 was identified to cause the conditional phenotype of the mutant initially studied. Similar to CAB1, genes YIL083C, YKL088W, YGR277C and YDR106C responsible for late CoA biosynthesis turned out as essential. Null mutants could be complemented by their bacterial counterparts coaBC, coaD and coaE, respectively. Comparative expression analyses showed that some CoA biosynthetic genes are weakly de-repressed with ethanol as a carbon source compared with glucose.