Isolation and characterization of Schizosaccharomyces pombe mutants defective in cell wall (1-3)beta-D-glucan

作者：Juan Carlos Ribas, Margarita Díaz, Abraham Madroñal Durán, Pilar Pérez · 发表于：Journal of Bacteriology · 年份：1991 · DOI：10.1128/jb.173.11.3456-3462.1991 · 被引用次数：101 · 研究领域：Polysaccharides and Plant Cell Walls、Biofuel production and bioconversion、Enzyme Production and Characterization

Schizosaccharomyces pombe thermosensitive mutants requiring the presence of an osmotic stabilizer to survive and grow at a nonpermissive temperature were isolated. The mutants were genetically and biochemically characterized. In all of them, the phenotype segregated in Mendelian fashion as a single gene which coded for a recessive character. Fourteen loci were defined by complementation analysis. Studies of cell wall composition showed a reduction in the amount of cell wall beta-glucan in three strains (JCR1, JCR5, and JCR10) when growing at 37 degrees C. Galactomannan was diminished in two others. Strains JCR1 and JCR5, with mutant alleles cwg1-1 and cwg2-1, respectively, were further studied. The cwg1 locus was mapped on the right arm of chromosome III, 18.06 centimorgans (cM) to the left of the ade5 marker; cwg2 was located on the left arm of chromosome I, 34.6 cM away from the aro5 marker. (1-3)beta-D-Glucan synthase activities from cwg1-1 and cwg2-1 mutant strains grown at 37 degrees C were diminished, as measured in vitro, compared with the wild-type strain; however, Km values and activation by GTP were similar to the wild-type values. Mutant synthases behaved like the wild-type enzyme in terms of thermostability. Analyses of round shape, lytic behavior, and low (1-3)beta-D-glucan synthase activity in cultures derived from ascospores of the same tetrad showed cosegregation of all these characters. Detergent dissociation of (1-3)beta-D-glucan synthase into soluble and pa...