Arakawa Y, Ohta M, Wacharotayankun R, Mori M, Kido N, Ito H, Komatsu T, Sugiyama T, Kato N
Department of Bacteriology, Nagoya University School of Medicine, Aichi, Japan.
Infect Immun. 1991 Jun;59(6):2043-50. doi: 10.1128/iai.59.6.2043-2050.1991.
The genes determining the biosynthesis of type 2 (K2) capsular polysaccharide [3----beta Glc1,4----beta Man(1,3----beta GlcUA) 1,4----alpha Glc1----] of Klebsiella pneumoniae Chedid (O1:K2), which is highly virulent for mice, were cloned and introduced into Escherichia coli HB101 and into four noncapsulated mutants derived from K. pneumoniae reference strains of K1, K7, K9, and K28. The recombinant plasmid pCPS7B06 carried 23 kb of a chromosomal DNA fragment of strain Chedid and encoded a part of the Klebsiella cps gene cluster. However, pCPS7B06 encoded enough genetic information for the production of Klebsiella K2 capsular polysaccharide on the cell surfaces of four noncapsulated mutants of K. pneumoniae. On the other hand, both pCPS7B06 and pROJ3 carrying the rmpA gene locus derived from a resident large plasmid of Chedid were required for the biosynthesis of Klebsiella K2 capsular polysaccharide on the cell surface of E. coli HB101. The insertion inactivation analysis using Tn5 revealed that the cps gene cluster occupied more than 15 kb of the chromosome of Chedid. We conclude that rmpA, which has been known to enhance the biosynthesis of colanic acid in E. coli, is also involved in the biosynthesis of Klebsiella capsular polysaccharide in E. coli HB101.
对小鼠具有高毒力的肺炎克雷伯菌Chedid（O1:K2）2型（K2）荚膜多糖[3----β-葡萄糖1,4----β-甘露糖(1,3----β-葡萄糖醛酸) 1,4----α-葡萄糖1----]生物合成相关基因进行了克隆，并导入大肠杆菌HB101以及从肺炎克雷伯菌K1、K7、K9和K28参考菌株衍生而来的4个无荚膜突变体中。重组质粒pCPS7B06携带了Chedid菌株23 kb的染色体DNA片段，并编码了肺炎克雷伯菌cps基因簇的一部分。然而，pCPS7B06编码了足够的遗传信息，可使4个肺炎克雷伯菌无荚膜突变体的细胞表面产生肺炎克雷伯菌K2荚膜多糖。另一方面，在大肠杆菌HB101的细胞表面合成肺炎克雷伯菌K2荚膜多糖需要pCPS7B06和携带源自Chedid常驻大质粒的rmpA基因座的pROJ3。利用Tn5进行的插入失活分析表明，cps基因簇在Chedid染色体上占据了超过15 kb的区域。我们得出结论，已知能增强大肠杆菌中结肠酸生物合成的rmpA，也参与了大肠杆菌HB101中肺炎克雷伯菌荚膜多糖的生物合成。
