Ribonuclease T1

Ribonuclease T1
Ribonuclease T1 from Aspergillus oryzae.[1]
Identifiers
Symbol	?
PDB	1YGW
UniProt	P00651
Other data
EC number	3.1.27.3

Ribonuclease T₁ (sometimes abbreviated RNase T₁) is a fungal endonuclease that cleaves single-stranded RNA after guanine residues, i.e., on their 3' end; the most commonly studied form of this enzyme is the version found in the mold Aspergillus oryzae. Owing to its specificity for guanine, RNase T₁ is often used to digest denatured RNA prior to sequencing. Similar to other ribonucleases such as barnase and RNase A, ribonuclease T₁ has been popular for folding studies.^[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.^[6]

References

External links

• MeSH Ribonuclease+T1

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