Figure 2. Plasmids for E. coli HisRS/tRNA^His and confirmation of E. coli tRNA^His expression in C. crescentus.

A, A schematic representation of expression units for E. coli HisRS, and tRNA^His. The gene of E. coli HisRS was cloned to NdeI and EcoRI sites of pBXMCS-2 or pBX-lac2. The tRNA^His units were inserted into EcoRI and SmaI sites. E. coli tRNA^His is transcribed as a precursor from the ffs promoter and then processed to generate the mature tRNA^His (in green). The flanking sequence is shown in light green. B, Northern blot analysis of E.coli tRNA^His from C. crescentus cultures. 0.5 fmol of in vitro transcripts of E. coli tRNA^His was used as a control. Eco tRNA^His _CUA and Eco tRNA^His2 _CUA stand for total RNAs from the cells containing pBX-HisRS-tRNA^His _CUA and pBX-HisRS-tRNA^His2 _CUA, respectively. Cells were grown in presence or absence of 0.2% xylose.