Synthesis and properties of N-acetyl-N'-(p-glyoxylylbenzoyl)cystamine, a new reagent for RNA-RNA and RNA-protein cross-linking.

The synthesis of N-acetyl-N'-(p-glyoxylylbenzoyl)cystamine (Gbz-Cyn2-Ac) is described. Like other glyoxal-type reagents it reacts with guanine and arginine. The kinetics and pH dependence of these reactions are studied. (Gbz-Cyn2-Ac) reacts with non-base-paired guanines at about 20 sites in 16-S rRNA. After reduction of disulfide bonds each derivatized guanine residue carries a free -- SH group which can be used to create RNA-RNA bridges or, after introducing an additional photoactivatable derivative, RNA-protein bridges.