The 2-thiouridine unit in the RNA strand is desulfured predominantly to 4-pyrimidinone nucleoside under in vitro oxidative stress conditions.

The 2-thiouridine (S2U) unit in the RNA strand is predominantly desulfured with H(2)O(2) to 4-pyrimidinone nucleoside (H2U). The resulting H2U-RNA exhibits significantly lower binding affinity to its complementary strand and in certain conditions undergoes strand scission. These results may explain the tRNA loss of biological function in oxidative stress conditions. © The Royal Society of Chemistry 2011