We first took a closer look at cyanobacterial endotoxins when we envisaged reliable, if possible homologous, effectors for synthetic biology biosafety devices. There was only one report in the literature about a cyanobacterial toxin/antitoxin module in Synechocystis PCC 6803 at that time, but it is expected that there are 36 encoded in its genome (according to the TADB database).

Using bioinformatics tools, we examined all the putative TA pairs in the genome of PCC 6803 and picked two that seemed promising for a detailed examination. Cloning in E. coli was a difficult task as some of the toxin obviously was active in the cells because of promoter leakage. Indirectly, this was a proof that we deal with active TA pairs. In the meantime, another paper appeared in the literature on a TA pair from the same strain (luckily, not our pairs were described!).

We are currently isolating reasonable amounts of both toxin and antitoxin to investigate their interaction. This work is in cooperation with the group of Prof. Jurij Lah (Physical Chemistry), just one floor above us.