抄録
In the cyanobacterium, Synechococcus sp. PCC 7942, the smt locus is responsible for tolerance to zinc and cadmium. In the smt locus, there are two divergently transcribed genes, smtA and smtB, encoding class II metallothionein (SmtA) and the trans-acting repressor for smtA expression (SmtB). SmtB also has the function for sensing zinc or cadmium ion concentration in the cell. With the heteronuclear multidimensional NMR and Resonance Raman spectroscopy for site-specifically mutated proteins, we studied the relationships between the functions and the structure of SmtB. With respect to the sensing of zinc-ion concentration and the smtA gene regulation, we found that the structural changes induced by the zinc-ion binding regulate the functions of SmtB as the smtA gene repressor.
