(S)-mchm5U is a hydroxylated form of mcm5U, may be present in tRNA from the silkworm Bombyx mori. (S)-mchm5U may be present also in mammalian tRNA, and that the ALKBH8 oxygenase could be responsible for its formation. (S)-mchm5U can be used for RNA modification synthesis.
References:
[1]. van den Born E, et al. ALKBH8-mediated formation of a novel diastereomeric pair of wobble nucleosides in mammalian tRNA. Nat Commun. 2011 Feb 1;2:172.