Difference between revisions of "Part:BBa K1378001"

MlrA is one part of the gene cluster responsible for the ability of MC degradation. The cluster includes four ORFs, ''mlrA, mlrB, mlrC and mlrD'', which can hydrolyze MCs and facilitate absorption of the products as carbon source. MlrA is sometimes referred as a metalprotease by inhibitor studies.

MlrA can cleavage the Adda-Arg bond and causes ring opening.(Fig. 1) The first-step linearized product shows much weaker hepatoxin compared with MCs. In the experiment of mouse bioassay, up to 250 mg/kg of linearized MC-LR shows no toxicity to mouse, much higher than 50% lethal dose 50mg/kg of cyclic MC-LR. Furthermore, the linearization also raise the median inhibition concentration to 95nM, around 160 times higher than original 0.6nM. ^[1]

MlrA exhibits high degradation activity in lysis culture. Its activity in living cells, however, has no difference with control group (Fig. 6b) This result suggests that our bacteria are unable to deal with MC immediately until they commit suicide. Thus, secretion system PelB is introduced. The PelB is linked to N-terminal of MlrA and the fusion protein is inserted into expression vector. We hope this measure would improve degradation effect largely in whole cell level.

References

[1] Gehringer, M. M., Milne, P., Lucietto, F., & Downing, T. G. (2005). Comparison of the structure of key variants of microcystin to vasopressin. Environmental toxicology and pharmacology, 19(2), 297-303.

Sequence and Features

Characterization

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