Difference between revisions of "Part:BBa K4324101"

Revision as of 11:39, 2 October 2022

Xylitol Dehydrogenase from S. cerevisiae

Sequence and Features

This part is the CDS of the XYL2 gene from S. cerevisiae that induces xylitol dehydrogenase, and has been codon-optimised for expression in E. coli.

Figure 1: Protein structure of xylitol dehydrogenase from AlphaFold

Usage and Biology

Our project focused on the improvement of xylose utilisation in E. coli. One part of this process was to incorporate a yeast-derived XR-XDH pathway

Figure 1: Xylose metabolism pathways of various microorganisms, from Biochemical routes for uptake and conversion of xylose by microorganisms by Zhao, Z., Xian, M., Liu, M. et al.

Xylitol dehydrogenase (EC 1.1.1.9), an oxidoreductase, is an enzyme that serves as a catalyst for the conversion of xylitol into xylulose, and vice versa, according to the following chemical equation:

In S. cerevisiae yeast cells, xylitol dehydrogenase forms the second process in the XR-XDH pathway, as shown in Figure 1, which converts xylose into xylulose via xylitol. Xylulose is then converted into xylulose-5-phosphate (X5P) for further metabolism in the pentose phosphate pathway.

E. coli do not exhibit the XR-XDH pathway, instead having an XI pathway that directly converts xylose into xylulose. Hence, together with xylose reductase (BBa_K4324100) which can convert xylose to xylitol, xylitol dehydrogenase presents an alternate xylose metabolism pathway for E. coli.

Furthermore, xylitol dehydrogenase enables E. coli to utilise xylitol as an energy source through its direct conversion to xylulose, which then follows the pentose phosphate pathway.

25mM

Characterisation

Proof of Expression

Proof of Function

References

1. https://www.uniprot.org/uniprotkb/Q07993/entry
2. https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-020-1662-x