Tajima K, Tanio T, Kobayashi Y, Kohno H, Fujiwara M, Shiba T, Erata T, Munekata M, Takai M
Division of Molecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo, Japan.
DNA Res. 2000 Aug 31;7(4):237-42. doi: 10.1093/dnares/7.4.237.
The levansucrase gene (lsxA) was cloned from the genomic DNA of Acetobacter xylinum NCI 1005, and the nucleotide sequence of the lsxA gene (1,293 bp) was determined. The deduced amino acid sequence of the lsxA gene showed 57.4% and 46.2% identity with the levansucrases from Zymomonas mobilis and Erwinia amylovora, respectively, while only 35.2% identity with that from Acetobacter diazotrophicus. The gene product of lsxA (LsxA) that was overproduced in E. coli coded for a polypeptide of molecular mass 47 kDa. The LsxA released glucose and produced polysaccharide from sucrose, the structure of which was analyzed by nuclear magnetic resonance spectroscopy and determined to be a beta-(2,6)-linked polyfructan.
从木醋杆菌NCI 1005的基因组DNA中克隆出了果聚糖蔗糖酶基因（lsxA），并测定了lsxA基因的核苷酸序列（1293 bp）。lsxA基因推导的氨基酸序列与运动发酵单胞菌和梨火疫病菌的果聚糖蔗糖酶分别具有57.4%和46.2%的同一性，而与重氮营养醋杆菌的果聚糖蔗糖酶只有35.2%的同一性。在大肠杆菌中过量表达的lsxA基因产物（LsxA）编码一种分子量为47 kDa的多肽。LsxA从蔗糖中释放出葡萄糖并产生多糖，其结构通过核磁共振光谱分析，确定为β-(2,6)-连接的多聚果糖。
