merR MEKNLENLTIGVFAKAAGVNVETIRFYQRKGLLPEPDKPYGSIRRYGEADVTRVRFVKSAQRLGFSLDEIAELLRLDDGTHCEEASSLAEHKLQDVREKMTDLARMETVLSELVFACHARQGNVSCPLIASLQGEKEPRGADAV MERR_SERMA 144 Mediates the mercuric-dependent induction of mercury resistance operon. In the absence of mercury merR represses transcription by binding tightly to the mer operator region; when mercury is present the dimeric complex binds a single ion and becomes a potent transcriptional activator, while remaining bound to the mer site. Mercuric resistance operon regulatory protein