... this position being positively charged in nearly 60% of ribosome-inactivating proteins [28]. TheMonzingo and Robertus models [10], and the 29meroligonucleotide-binding model of Olson and Cuff ... challenged withincreasing concentrations of toxin at 37 °C for 4 h. Remaining proteinsynthesis after this time was measured by the incorporation of (35S)methionine. Symbols indicate the mean of four ... ricin, d, ricin R213A, j;andricinR213D, m.(B)ricin,d; ricin R258A, j, and ricin R258D, m;(C)ricin,d; ricin R48A, j.Fig. 2. Assessment of the N-glycosidase activity of RTA variants con-taining...