Novel putative galactose operon involving lacto-N-biose phosphorylase in Bifidobacterium longum
Novel putative galactose operon involving lacto-N-biose phosphorylase in Bifidobacterium longum
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DOI：
10.1128/aem.71.6.3158-3162.2005
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发表时间：
2005-06-01
影响因子：
4.4
通讯作者：
Nishimoto, M
中科院分区：
文献类型：
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作者：
Kitaoka, M;Tian, JS;Nishimoto, M
从两歧双歧杆菌的细胞提取物中纯化出乳-N-二糖磷酸化酶（LNBP）。其N端和内部氨基酸序列与BL1641基因编码的长双歧杆菌NCC2705的假设蛋白的序列同源。模式菌株B. longum JCM1217的同源基因lnpA在大肠杆菌中表达，证实其编码LNBP。没有发现与任何具有已知功能的蛋白质有显着的同一性，这表明 LNBP 应该被分类到一个新的家族中。 lnpA 基因位于一个新的半乳糖代谢推定操纵子中，该操纵子不含半乳糖激酶基因。操纵子似乎参与了粘蛋白糖代谢介导的双歧杆菌的肠道定植。此外，它还可以解决母乳中双歧因子的性质问题，即乳寡糖中发现的乳-N-二糖结构。
A lacto-N-biose phosphorylase (LNBP) was purified from the cell extract of Bifidobacterium bifidum. Its N-terminal and internal amino acid sequences were homologous with those of the hypothetical protein of Bifidobacterium longum NCC2705 encoded by the BL1641 gene. The homologous gene of the type strain B. longum JCM1217, lnpA, was expressed in Escherichia coli to confirm that it encoded LNBP. No significant identity was found with any proteins with known function, indicating that LNBP should be classified in a new family. The lnpA gene is located in a novel putative operon for galactose metabolism that does not contain a galactokinase gene. The operon seems to be involved in intestinal colonization by bifidobacteria mediated by metabolism of mucin sugars. In addition, it may also resolve the question of the nature of the bifidus factor in human milk as the lacto-N-biose structure found in milk oligosaccharides.