Difference between revisions of "Part:BBa K1197013"

Latest revision as of 03:33, 5 October 2013

CYP6G1 - Insecticide resistance gene

It is an insecticide resistance gene which is found in Drosophila melanogaster. We used it in our system to metabolize imidacloprid by producing nontoxic byproducts.

It is obtained from Drosophila melanogaster genome and modified according to work in B.subtilis.

Original sequence was modified since it was not proper for prokaryotic expression. Its first 21 nucleotide which coding 7 aa was changed with "Barnes" sequence: MVLTEVL is the native aa sequence, and MALLLAV is the Barnes aa sequence. (Barnes et al. 1991)

Reference: Barnes, H.J., Arlotto, M.P., Waterman, M.R., 1991. Expression and enzymatic activity of recombinant cytochrome P450 17a-hydroxylase in Escherichia coli. Proc. Natl. Acad. Sci. USA 88, 5597e5601.

• P450 Monooxgenase Production and its Activity:

As seen in the circuit, CYP6G1 gene , which will produce P450, is synthesized by using B. subtilis specific constituve promoter Pveg. fCPR gene, used for activation of CYP6G1 in B. subtilis, is also transcribed with same promoter. These two genes has transcribed with SacB genes, after translation which helps to export these proteins through outside of the cell, into the bee gut. [1] To be able know, how much enzyme is produced in a given time and how much imidacloprid is converted into nontoxic components by P450, model of this circuit was required.

Enzyme Kinetics for P450 Monooxygenase:

To be able to estimate the rate of the P450 reaction with imidacloprid, we used Michaelis-Menten Kinetics. The harmful imidacloprid concentration for honey bees is reported as 1200 µg/l [2], so in our model we assumed that the imidacloprid concentration in bee gut as 1200 µg/l. And P450 monooxgenase will be produced from our circuit and directly secreted into bee gut where imidacloprid is found.

Sequence and Features