Part:BBa_K4192021

obcB, one of the genes required for oxalic acid synthesis

It is one of the genes required for oxalic acid synthesis in Burkholderia glumae, which can act together with ObcB to catalyze oxaloacetic acid (OAA) and citric acid to form oxalic acid (OA). When there is only ObcB, it cannot form oxalic acid.

Biology

CAU_China 2022 used this part in their oxalate secretion circuit and the expression product of obcB is one of the main enzyme in in the oxalate secretion circuit^[1]. It can act together with ObcA to catalyze oxaloacetic acid (OAA) and citric acid to form oxalic acid (OA). When there is only ObcB, it cannot form oxalic acid^[2].

Fig.1 Effects of obcA and obcB, the shade of purple reflects the concentration of oxalic acid^[1].

When producing oxalic acid, obcB turns C6-CoA adduct into CoA, acetoacetate,and oxalic acid

Fig.2 Mechanism of obcA and obcB^[2].

Considering the importance of obcA and obcB occur togrther in the biosynthesis of oxalic acid, the CDS of them are in close proximity to each other, even encoded on a single polycistronic message. The implication of this for our project is that we can make these two genes share the same promoter^[2].

Fig.3 Distribution of obcA and obcB^[1].

We constructed a separate pET-obcB plasmid, and determined that the ObcB protein can be successfully expressed in E.coli BL21 (DE3) through SDS-PAGE, the results are as follows:

Fig.4 Obc protein in SDS-PAGE.