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VIT Vellore

We use a plasmid system consisting of a composite part with two promoters

This part gets activated at ~pH 7.5 and produces the necessary proteins to increase the surrounding pH

Repressor molecule LexA is produced at high pH. LexA then binds to its operator region in the initial plasmid, and represses carbonic anhydrase

LexA functions as a repressor in the above figure. However, as the pH starts to become acidic again, recA protease is produced

recA protease binds to LexA (repressor) and lyses it, thereby preventing its action. Carbonic anhydrase is produced again, and pH homeostasis is ensured