Owing to its specificity for guanine, RNase T1 is often used to digest denatured RNA prior to sequencing.

[2] Structurally, ribonuclease T1 is a small α+β protein (104 amino acids) with a four-stranded, antiparallel beta sheet covering a long alpha helix (almost five turns).

RNase T1 has two disulfide bonds, Cys2-Cys10 and Cys6-Cys103, of which the latter contributes more to its folding stability;[3] complete reduction of both disulfides usually unfolds the protein, although its folding can be rescued with high salt concentrations.

[4] RNase T1 also has four prolines, two of which (Pro39 and Pro55) have cis isomers of their X-Pro peptide bonds.

Nonnative isomers of these prolines can retard conformational folding dramatically,[5] folding on a characteristic time scale of 7,000 seconds (almost two hours) at 10 °C and pH 5.