Brzywczy Jerzy, Sieńko Marzena, Kucharska Agnieszka, Paszewski Andrzej
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5A, 02-106 Warszawa, Poland.
Yeast. 2002 Jan 15;19(1):29-35. doi: 10.1002/yea.798.
Schizosaccharomyces pombe, in contrast to Saccharomyces cerevisiae and Aspergillus nidulans, lacks cystathionine beta-synthase and cystathionine gamma-lyase, two enzymes in the pathway from methionine to cysteine. As a consequence, methionine cannot serve as an efficient sulphur source for the fungus and does not bring about repression of sulphur assimilation, which is under control of the cysteine-mediated sulphur metabolite repression system. This system operates at the transcriptional level, as was shown for the homocysteine synthase encoding gene. Our results corroborate the growing evidence that cysteine is the major low-molecular-weight effector in the regulation of sulphur metabolism in bacteria, fungi and plants.
与酿酒酵母和构巢曲霉不同，粟酒裂殖酵母缺乏胱硫醚β-合酶和胱硫醚γ-裂解酶，这是从甲硫氨酸到半胱氨酸途径中的两种酶。因此，甲硫氨酸不能作为该真菌的有效硫源，也不会导致硫同化的抑制，而硫同化受半胱氨酸介导的硫代谢物阻遏系统控制。如在同型半胱氨酸合酶编码基因中所示，该系统在转录水平上起作用。我们的结果证实了越来越多的证据，即半胱氨酸是细菌、真菌和植物硫代谢调节中主要的低分子量效应物。
