Part:BBa_K2963033

racE- encoding racemase

This part contains the racE racemase gene, which was constructed using the tac (BBa_K864400) promoter, rbs (BBa_K2963006), racE gene (BBa_K2963004) and the T7 terminator (BBa_K2598024). This part was compared with the other part (BBa_K2963033) which contained another lac operator follwowing the tac promoter（BBa_K864400）.Simultaneously, the rest basic parts are the same. The racemase activity data and real-time PCR data were used to characterize the composite part. And we compared the different expression levels of racE gene of the two composite parts(BBa_K2963033 and BBa_K2963032）.

Usage and Biology

The racE gene is a type of racemase gene from Bacillus subtilis while in Bacillus licheniformis is named glr. According to previous reports, glr has two characters against L-glutamic acid, one is weak affinity and the other is strong catalytic properties.

Characterization

Figure 1. The expression level of the racemase gene racE at 8h,16h,24h decreased by 29.99%, 58.86% and 62.34% respectively. The results show that the expression intensity of racE was effectively reduced at each transcriptional stage by the tandem of two lacOs compared to one lacO.

Figure 2. We tested the enzyme activity of the racemase in cells. The result was the same as the above and the enzyme activity was different.