Part:BBa_K1602017

D-xylonic acid producing operon

D-Xylose is a monosaccharide belonging to the aldopentose family. It was recently shown that the D-xylose dehydrogenase xylB from Caulobacter crescentus can convert D-xylose to D-xylonolactone. This can react spontaneously or through the catalysation of xylC to D-xylonic acid. In E. coli D-xylonic acid can be further metabolized to ethyleneglycol.

Figure 1 Sheme of the reactions catalyzed by xylB and xylC. The xylC reaction can also happen spontaneously but in a much lower speed.

Usage

This part is a composite of two coding genes with strong RBS (BBa_B0034). The transcription is controlled by a T7 promotor (BBa_I719005).

T7-promotor (BBa_I719005) ribosome binding site B0034 (BBa_B0034) D-xylose dehydrogenase xylB (BBa_K1602009) D-xylonolactone lactonase xylC (BBa_K1602010)
	Figure 2

Results

The expression of cadA has been visualized via SDS-PAGE. Positive clones were grown at 37° celsius until an OD of 0,7. Afterwards the cells were induced utilizing 20µl of 1M IPTG for 12h at 28° celsius. Finally the cells were lysated via ultrasonic cell disruption.

Figure 3 Scan of the PAGE containing from left to right a marker (M; Protein Marker III AppliChem), the positive sample (1) and a negative control (2). The picture was cropped and edited for clarification purposes.	Figure 4 Plot of the gel lanes based on contrast analyses - created with ImageJ

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Sequence and Features

=== BBa_K1602017 SequenceAndFeatures
===References=== 1. Liu H, Ramos KR, Valdehuesa KN, Nisola GM, Lee WK, Chung WJ. Biosynthesis of ethylene glycol in Escherichia coli. Appl Microbiol Biotechnol. 2013;97(8):3409-17. 2. Toivari MH, Nygard Y, Penttila M, Ruohonen L, Wiebe MG. Microbial D-xylonate production. Appl Microbiol Biotechnol. 2012;96(1):1-8.