Guanosine in a single stranded region of anticodon stem-loop tRNA models is prone to oxidatively generated damage resulting in dehydroguanidinohydantoin and spiroiminodihydantoin lesions.

Oxidation of RNA hairpin models corresponding to anticodon stem-loop (ASL) of transfer RNA led to RNA damage consisting solely of a unique loop guanine oxidation. Manganese porphyrin/oxone treatment of RNA resulted in dehydroguanidinohydantoin (DGh; major) and/or spiroiminodihydantoin (Sp) lesions. Ribose damage was not observed. This two-electron transfer oxidation reaction allowed the identification of guanine oxidation products for further study of RNA species carrying a unique lesion at a single G to investigate their biological impact.