Met Repressor, MetJ. MetJ is a bacterial regulatory protein that uses S-adenosylmethionine (SAM) as a corepressor to regulate the production of Methionine. MetJ binds arrays of two to five adjacent copies of an eight base-pair 'metbox' sequence. MetJ forms sufficiently strong interactions with the sugar-phosphate backbone to accomodate sequence variation in natural operators. However, it is very sensitive to particular base changes in the operator. MetJ exists as a homodimer.
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