Biosynthesis of hydroxymethylpyrimidine pyrophosphate in Saccharomyces cerevisiae
Biosynthesis of hydroxymethylpyrimidine pyrophosphate in Saccharomyces cerevisiae
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DOI：
10.1007/s00294-004-0557-x
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发表时间：
2005-03-01
期刊：
影响因子：
2.5
通讯作者：
Nosaka, K
中科院分区：
文献类型：
--
作者：
Kawasaki, Y;Onozuka, M;Nosaka, K
酿酒酵母的两个冗余基因THI 20和THI 21编码硫胺素生物合成所需的2-甲基-4-氨基-5-羟甲基嘧啶一磷酸（HMP-P）激酶。使用功能互补分析与大肠杆菌突变株和一个定义的生化系统，含有部分纯化的蛋白质的重组硫胺素单磷酸合成，我们证明，这两个Thi 20 p和Thi 21 p蛋白质也有HMP激酶活性。尽管每个亚型都可以独立地从HMP合成HMP焦磷酸（HMP-PP），但这两种蛋白质之间的效率存在显着差异。thi 20缺失菌株在不含硫胺素的基本培养基中以与亲本菌株相同的速率生长，但其从HMP合成HMP-PP的能力显著降低。我们讨论了HMP不参与S.啤酒。
Two redundant genes, THI20 and THI21, of Saccharomyces cerevisiae encode a 2-methyl-4-amino-5-hydroxymethylpyrimidine monophosphate (HMP-P) kinase required for thiamin biosynthesis. Using functional complementation analysis with an Escherichia coli mutant strain and a defined biochemical system containing partially purified proteins for the reconstitution of thiamin monophosphate synthesis, we demonstrate that both Thi20p and Thi21p proteins also have HMP kinase activity. Although each isoform independently can synthesize HMP pyrophosphate (HMP-PP) from HMP, there is a marked difference in efficiency between the two proteins. The thi20 deletion strain grows at the same rate as the parental strain in minimal medium without thiamin, but its ability to synthesize HMP-PP from HMP is significantly decreased. We discuss the possibility that HMP is not involved in the pathway of de novo thiamin synthesis in S. cerevisiae.