Sulphur amino acid synthesis in Schizosaccharomyces pombe represents a specific variant of sulphur metabolism in fungi

Abstract

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.

Comparative Genomics of Enzymes in Flavor-Forming Pathways from Amino Acids in Lactic Acid Bacteria

“…The third major subfamily contains unifunctional AHSH enzymes, as suggested by the experimentally characterized cysD gene from the fungus Emericella nidulans and other microorganisms (15,59,60). Notably, almost all of the LAB species/strains that contain a member of the AHSH subfamily also seem to contain a CGS/AHSH subfamily member, except for Oenococcus oeni.…”

Sulfur Transfer through an Arbuscular Mycorrhiza

“…This pathway is crucial in Saccharomyces cerevisiae, where sulfide is assimilated not though Cys synthase, but through the sulfhydrolation of O-acetylhomoserine to form homo-Cys, from which Met is made Ono et al, 1999). By contrast, Schizosaccharomyces pombe has been shown to be deficient in reverse trans-sulfuration pathway enzymes, making it dependent on Cys synthase for S assimilation (Brzywczy et al, 2002). This results in a reduced regulatory role for Met in S. pombe (Brzywczy et al, 2002).…”

“…By contrast, Schizosaccharomyces pombe has been shown to be deficient in reverse trans-sulfuration pathway enzymes, making it dependent on Cys synthase for S assimilation (Brzywczy et al, 2002). This results in a reduced regulatory role for Met in S. pombe (Brzywczy et al, 2002). There is also evidence that the S assimilation enzymes are transcriptionally regulated in S. cerevisiae specifically by levels of Cys (Hansen and Johannesen, 2000).…”

Characterization of Two Genes Encoding Putative Cysteine Synthase Required for Cysteine Biosynthesis inSchizosaccharomyces pombe

“…Thus, a block of the cystathionine pathway due to a mutation of CYS3/ STR1 coding for cystathionine -lyase causes cysteine auxotrophy. 6,7) The fission yeast Schizosaccharomyces pombe has been reported to lack the cystathionine pathway and to synthesize cysteine only via the OAS pathway 8,9) (Fig. 1-ii).…”

“…Therefore it is expected that cysteine synthase is pombe (ii). Partially cited from Brzywczy et al 9) a, cystathionine -lyase; b, cysteine synthase. The OAS pathway and cystathionine pathway are respectively indicated with dotted squares.…”