Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM. Calle Arturo Duperier 4, 28029, Madrid, Spain.
Sci Rep. 2018 Nov 16;8(1):16949. doi: 10.1038/s41598-018-35045-8.
Saccharomyces cerevisiae can transport and phosphorylate glucosamine, but cannot grow on this amino sugar. While an enzyme catalyzing the reaction from glucosamine-6-phosphate to fructose-6-phosphate, necessary for glucosamine catabolism, is present in yeasts using N-acetylglucosamine as carbon source, a sequence homology search suggested that such an enzyme is absent from Saccharomyces cerevisiae. The gene YlNAG1 encoding glucosamine-6-phosphate deaminase from Yarrowia lipolytica was introduced into S. cerevisiae and growth in glucosamine tested. The constructed strain grew in glucosamine as only carbon and nitrogen source. Growth on the amino sugar required respiration and caused an important ammonium excretion. Strains overexpressing YlNAG1 and one of the S. cerevisiae glucose transporters HXT1, 2, 3, 4, 6 or 7 grew in glucosamine. The amino sugar caused catabolite repression of different enzymes to a lower extent than that produced by glucose. The availability of a strain of S. cerevisiae able to grow on glucosamine opens new possibilities to investigate or manipulate pathways related with glucosamine metabolism in a well-studied organism.
酿酒酵母可以运输和磷酸化氨基葡萄糖，但不能在这种氨基糖上生长。虽然在使用 N-乙酰氨基葡萄糖作为碳源的酵母中存在一种酶，可以将氨基葡萄糖-6-磷酸转化为果糖-6-磷酸，这是氨基葡萄糖分解代谢所必需的，但序列同源性搜索表明，酿酒酵母中不存在这种酶。来自解脂耶氏酵母的 YlNAG1 基因编码氨基葡萄糖-6-磷酸脱氨酶，被引入酿酒酵母并测试其在氨基葡萄糖上的生长情况。构建的菌株仅以氨基葡萄糖作为碳源和氮源生长。在这种氨基糖上的生长需要呼吸作用，并导致大量铵的排泄。过量表达 YlNAG1 和酿酒酵母葡萄糖转运蛋白 HXT1、2、3、4、6 或 7 之一的菌株可以在氨基葡萄糖上生长。与葡萄糖产生的情况相比，这种氨基糖对不同酶的分解代谢物抑制作用较小。能够在氨基葡萄糖上生长的酿酒酵母菌株的出现，为在一个研究充分的生物体中研究或操纵与氨基葡萄糖代谢相关的途径提供了新的可能性。
