Binding of methylmercuric hydroxide by 4-thiouridine of N-formylmethionyl-tRNA from Escherichia coli

Abstract

The binding of methylmercuric hydroxide to N-formylmethionyl-tRNA of E. coli was studied. In the absence of Mg2+, methylmercury binds strongly to 4-thiouridine in the 8th position from the 5'' end; the dissociation constant is (1.0 .+-. 0.2) .times. 10-5 M and the forward and reverse rate constants for binding are (5.3 .+-. 0.5) .times. 104 M-1 s-1 and 0.38 .+-. 0.02 s-1, respectively. The presence of Mg2+ prevents this binding, presumably through some conformational change induced in the structure of N-formylmethionyl-tRNA.