BBa_K1813026

Cch2 is a novel chlorohydrolase that was identified in a soil bacterium, Bradyrhizobiaceae strain SG-6C, that is capable of dechlorinating 6-chloronicotinic acid (6-CNA) to 6-hydroxynicotinic acid (6-HNA). 6-CNA has been found to accumulate in soils and plant material following application of imidacloprid. Due to the associated toxicity of 6-CNA to bees, demonstrating that this part can be used to degrade 6-CNA to 6-HNA, a less toxic metabolite, was a big accomplishment (see data here). rem ipsum dolor sit amet, consectetur adipiscing elit. Sed posuere eget nulla a pharetra. Suspendisse ac venenatis odio. Sed blandit posuere erat a posuere. Suspendisse odio erat, elementum sodales ante vel, malesuada rutrum turpis.

BBa_K1813064

This composite part consists of CYP6G1 is a cytochrome P450 (CYP) from Drosophila melanogaster that can modify imidacloprid to 4- and 5-hydroxyimidacloprid. These degradation products have been demonstrated to be less toxic to bees. Previous work by Middle East Technical University (METU) had worked on this part (BBa_K1197013); however, it is not available from the registry. In attempts to make an improvement to this part, we included a pelB signal sequence immediately upstream of the gene to target CYP6G1 to the periplasm. Though we were not able to validate that this improved the part, previous literature on expression of CYP’s suggests that inclusion of a signal sequence greatly improves heterologous protein expression.

BBa_K1813067

The objective of our probeeotic project was to genetically modify a native bee gut microbe to be capable of degrading imidacloprid and 6-CNA. A step towards that goal included generating a construct that consisted of multiple imidacloprid modification genes and genes for complete mineralization of 6-CNA to fumarate. Unfortunately, we were unable to generate any data on this composite part as E. coli harboring this plasmid did not grow well in liquid media (see data here).

Composite parts: Imidacloprid modification

BBa_K1813064 CYP6G1 from D. melanogaster with N-terminal PelB signal sequence and Musca domestica (house fly) cytochrome P450 reductase. CYP6G1 can convert imidacloprid to 4- and 5-hydroxy imidacloprid.

BBa_K1813065 CYP6CM1 from Bemisia tabaci with N-terminal PelB signal sequence and Musca domestica (house fly) cytochrome P450 reductase. CYP6CM1 can convert imidacloprid to 5-hydroxy imidacloprid.

BBa_K1813066 CYP2D6 from human with N-terminal PelB signal sequence and Musca domestica (house fly) cytochrome P450 reductase. CYP6G1 can convert imidacloprid to nitrosoimine derivative.

Composite parts: 6-CNA Degradation

BBa_K1813026 Cch2 is from Bradyrhizobiaceae strain SG-6C for conversion of 6-CNA to 6-HNA.

BBa_K1813020 NicC is from Pseudmonas putida KT2240 for conversion of 6-HNA to 2,5-dihydroxypyridine

BBa_K1813031 NicX is from Pseudmonas putida KT2240 for conversion of 2,5-dihydroxypyridine to N-formylmaleamic acid

BBa_K1813021 NicD is from Pseudmonas putida KT2240 for conversion of N-formylmaleamic acid to maleamic acid

BBa_K1813022 NicE is from Pseudmonas putida KT2240 for conversion of maleamic acid to maleic acid

BBa_K1813023 NicF is from Pseudmonas putida KT2240 for conversion of maleic acid to fumarate

Composite parts: Multi-gene Pesticide Degradation

BBa_K1813035 Consists of the genes required for degradation of 6-CNA to fumarate. These include genes coding for Cch2, to convert 6-CNA to 6-HNA, and NicCXDEF, the five enzymes required for degradation of 6-HNA to fumarate. The end-product, fumarate can be funneled into central metabolism.

BBa_K1813067 Contains one of the three CYPs investigated, CYP6G1, cytochrome P450 reductase, cch2, and the nicCXDEF cluster. This construct would allow for modification of imidacloprid to a less toxic form by CYP6G1, conversion of 6-CNA to 6-HNA by Cch2, and degradation of 6-HNA to fumarate by NicCXDEF pathway.

BBa_K1813066 As above, but with CYP6CM1 in place of CYP6G1.

BBa_K1813072 Also as above, but with CYP2D6 in place of CYP6G1.