ABSTRACTWe have determined the functions of the enzymes encoded by thelnpB, lnpC, andlnpDgenes, located downstream of the lacto-N-biose phosphorylase gene (lnpA), inBifidobacterium longumJCM1217. ThelnpBgene encodes a novel kinase,N-acetylhexosamine 1-kinase, which producesN-acetylhexosamine 1-phosphate; thelnpCgene encodes UDP-glucose hexose 1-phosphate uridylyltransferase, which is also active onN-acetylhexosamine 1-phosphate; and thelnpDgene encodes a UDP-glucose 4-epimerase, which is active on both UDP-galactose and UDP-N-acetylgalactosamine. These results suggest that the gene operonlnpABCDencodes a previously undescribed lacto-N-biose I/galacto-N-biose metabolic pathway that is involved in the intestinal colonization of bifidobacteria and that utilizes lacto-N-biose I from human milk oligosaccharides or galacto-N-biose from mucin sugars.
摘要 我们确定了长双歧杆菌(Bifidobacterium longumJCM1217)中位于乳-N-
生物糖
磷酸化酶
基因(lnpA)下游的lnpB、lnpC和lnpD
基因所编码的酶的功能。lnpB
基因编码一种新型激酶--N-乙酰己糖胺1-激酶,它能产生N-乙酰己糖胺1-
磷酸;lnpC
基因编码
UDP-
葡萄糖己糖1-
磷酸尿苷酰转移酶,它也对N-乙酰己糖胺1-
磷酸有活性;lnpD
基因编码
UDP-
葡萄糖 4-酰化酶,它对
UDP-半
乳糖和
UDP-N-乙酰半
乳糖胺都有活性。这些结果表明,
基因操作子lnpABCD编码一个以前未描述过的
乳糖-N-
生物糖I/半
乳糖-N-
生物糖代谢途径,该途径参与双歧杆菌的肠道定植,并利用人乳低聚糖中的
乳糖-N-
生物糖I或粘
蛋白糖中的半
乳糖-N-
生物糖。