Prolyl 3,4-dihydroxylase that catalyzes 3,4-dihydroxylation of 'Pro-62' of small ribosomal subunit uS12 (rps23 and rps2302), thereby regulating protein translation termination efficiency. Negative regulator of the stability of the N-terminal transcription factor domain (Sre1N) of sre1 which is released from the membrane and enters the nucleus to activate hypoxic gene expression. 2-oxoglutarate + [ribosomal protein uS12]-L-proline + O2 = [ribosomal protein uS12]-(3S)-3-hydroxy-L-proline + CO2 + succinate 2-oxoglutarate + [ribosomal protein uS12]-(3S)-3-hydroxy-L-proline + O2 = [ribosomal protein uS12]-(3S)-3,4-dihydroxy-L-proline + CO2 + succinate Binds 1 Fe(2+) ion per subunit. Monomer and homodimer (By similarity). Interacts with nro1 (PubMed:19158663). Belongs to the TPA1 family.