Molecular mechanism of accumulation and rearrangement of antibiotic resistance gene in bacteria.

我们测定了粘质沙雷氏菌和恶臭假单胞菌临床分离株中3类整合子的遗传结构。包括3类整合子的核苷酸区域两侧有25bp的反向重复序列，并与被认为是3类整合子转座所必需的TniA、TniB、TniQ和TniC等元件位于同一位置。重组IntI3蛋白在大肠杆菌中表达，柱层析纯化，悬滴气相扩散法结晶。然而，我们无法从晶体中获得良好的X射线衍射数据。在鲍曼不动杆菌临床分离株中，ISAbaI位于bla_lt；OXA-51-like&gt；的上游，可能为相邻的bla_lt；Oxa-51-like&gt；的表达提供启动子活性。

We determined the genetic structure of class 3 integrons in Serratia marcescens and Pseudomonas putida clinical isolates. The nucleotide regions including class 3 integron were flanked by 25bp inverted repeats and co-located with the elements such as TniA, TniB, TniQ, and TniC, which are thought to be required for the transposition of class 3 integron. Recombinant IntI3 protein was expressed in Escherichia coli, purified using column chromatography, and crystallized by hanging drop vapor diffusion method. However, we could not obtain a good X-ray diffraction data from the crystals. In Acinetobacter baumannii clinical isolates, ISAbaI was located upstream of bla_<OXA-51-like>, and apperared to provide a promoter activity for expression of adjacent bla_<OXA-51-like>.