Nakano Y, Yoshida Y, Yamashita Y, Koga T
Department of Preventive Dentistry, Kyushu University Faculty of Dentistry, Fukuoka 812-8582, Japan.
Biochim Biophys Acta. 1998 Nov 8;1442(2-3):409-14. doi: 10.1016/s0167-4781(98)00174-2.
The serotype c antigen of Actinobacillus actinomycetemcomitans consists of 6-deoxy-l-talose. A gene cluster involved in the synthesis of serotype-specific polysaccharide antigen was cloned from the chromosomal DNA of A. actinomycetemcomitans NCTC 9710 (serotype c). This cluster consisted of 17 open reading frames. Escherichia coli produced the polysaccharide that reacts with the serotype c-specific antibody when transformed with a plasmid containing the cluster. Comparing the structure of the gene cluster with a similar cluster from A. actinomycetemcomitans Y4 (serotype b), which produces a polysaccharide consisting of l-rhamnose and d-fucose, revealed that a 5.7 kb region containing seven genes in the cluster from strain Y4 was replaced by a 3.8 kb region containing three genes in strain NCTC 9710. The results suggest that these region, as well as dTDP-6-deoxy-l-talose-forming dTDP-4-keto-l-rhamnose reductase, is essential to the production of extracellular polysaccharide specific to serotype c.
伴放线放线杆菌血清型c抗原由6-脱氧-L-塔罗糖组成。从伴放线放线杆菌NCTC 9710（血清型c）的染色体DNA中克隆了一个参与血清型特异性多糖抗原合成的基因簇。该基因簇由17个开放阅读框组成。当用含有该基因簇的质粒转化时，大肠杆菌产生与血清型c特异性抗体发生反应的多糖。将该基因簇的结构与来自伴放线放线杆菌Y4（血清型b）的类似基因簇进行比较，Y4产生的多糖由L-鼠李糖和D-岩藻糖组成，结果显示，Y4菌株基因簇中包含7个基因的5.7 kb区域被NCTC 9710菌株中包含3个基因的3.8 kb区域所取代。结果表明，这些区域以及形成dTDP-6-脱氧-L-塔罗糖的dTDP-4-酮-L-鼠李糖还原酶对于血清型c特异性细胞外多糖的产生至关重要。
