UV cross-linking of 3H-AdoMet to Trm5 and mutants examined by SDS-PAGE analysis. (A) Commassie-stained of a representative SDS-PAGE analysis of the wild-type Trm5, and the R144A, Y176A, G205A/G207A, D223A, and P267A mutants. The intensity of the stain indicates the quantity of the enzyme in the gel. (B) The SDS-PAGE used in (A) subjected to fluorography imaging of the cross-linked species.