There are a group of promoters from the genes for metallothioneins. These are a group of proteins rich in ______ residues.
(a) cysteine
(b) methionine
(c) either cysteine or methionine
(d) cysteine and methionine both
I had been asked this question in semester exam.
The above asked question is from Cultured Cells in Mammals and Restricted Areas in Intact Organisms in section Using Other Organisms of Genetic Engineering