Glucan synthesis in the genus Lactobacillus:: isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains
Glucan synthesis in the genus Lactobacillus:: isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains
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DOI：
10.1099/mic.0.27321-0
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发表时间：
2004-11-01
期刊：
影响因子：
2.8
通讯作者：
Dijkhuizen, L
中科院分区：
文献类型：
--
作者：
Kralj, S;van Geel-Schutten, GH;Dijkhuizen, L
链球菌属和明串珠菌属的成员合成各种α-谷氨酸(葡聚糖、交替多糖和变形)。在乳杆菌中，到目前为止，唯一已被鉴定的葡糖基转移酶(GTF)是鲁氏乳杆菌121的GTfA，这是第一个合成葡聚糖(Reuran)的GTIF酶，该酶主要含有α-(1->；4)键以及α-(1->；6)和α-(1-gt；4，6)键。最近，在乳杆菌属的其他成员中也发现了葡聚糖酶基因的部分序列。本文首次报道了各种乳杆菌的葡聚糖酶和变位蔗糖酶基因及酶的分离和鉴定，以及所合成的主要具有α-(1->；6)-和α-(1-->；3)-糖苷键的葡聚糖产物的性质。这四种GTF酶具有三种不同的Lb。Reuri株在氨基酸水平上高度相似，因此它们的蛋白质结构非常相似。有趣的是，这四磅。Reuri GTF有相对较大的N-末端可变区，包含RDV重复序列，以及相对较短的假定葡聚糖结合结构域，具有保守和较不保守的YG-重复单位。另外三种从乳杆菌、发酵乳杆菌和副乳杆菌分离的GTF酶，与Lb相比，含有更小的可变区和更大的推测的葡聚糖结合结构域。Reuri GTF酶。
Members of the genera Streptococcus' and Leuconostoc synthesize various alpha-gucans (dextran, alternan and mutan). In Lactobacillus, until now, the only glucosyltransferase (GTF) enzyme that has been characterized is gtfA of Lactobacillus reuteri 121, the first GTIF enzyme synthesizing a glucan (reuteran) that contains mainly alpha-(1 --> 4) linkages together with alpha -(1 --> 6) and alpha-(1 --> 4,6) linkages. Recently, partial sequences of glucansucrase genes were detected in other members of the genus Lactobacillus. This paper reports, for the first time, isolation and characterization of dextransucrase and mutansucrase genes and enzymes from various Lactobacillus species and the characterization of the glucan products synthesized, which mainly have alpha-(1 --> 6)- and alpha-(1 --> 3)-gIucosidic linkages. The four GTF enzymes characterized from three different Lb. reuteri strains are highly similar at the amino acid level, and consequently their protein structures are very alike. Interestingly, these four Lb. reuteri GTFs have relatively large N-terminal variable regions, containing RDV repeats, and relatively short putative glucan-binding domains with conserved and less-conserved YG-repeating units. The three other GTF enzymes, isolated from Lactobacillus sakei, Lactobacillus fermentum and Lactobacillus parabuchneri, contain smaller variable regions and larger putative glucan-binding domains compared to the Lb. reuteri GTF enzymes.