tRNA (cytidine56-2'-O)-methyltransferase (, aTrm<sup>56</sup>, tRNA ribose 2'-O-methyltransferase aTrm<sup>56</sup>, PAB1040 (gene)) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (cytidine56-2'-O)-methyltransferase. This enzyme catalyses the following chemical reaction
The archaeal enzyme specifically catalyses the S-adenosyl-L-methionine dependent 2'-O-ribose methylation of cytidine at position 56 in tRNA transcripts.