The MtnD ATG start codon has been replaced by a NotI site.
MtnAΔATG, MtnBΔATG, MtnCΔATG, MtnDΔATG has chemical sensitive phenotype
MtnAΔATG MtnBΔATG MtnCΔATG MtnDΔATG quadruple mutants show little or no survival on 1mM copper or 100mM cadmium concentrations in food compared to controls.