Transfers and isomerizes the ribose moiety from AdoMet to the 7-aminomethyl group of 7-deazaguanine (preQ1-tRNA) to give epoxyqueuosine (oQ-tRNA). 7-aminomethyl-7-carbaguanosine(34) in tRNA + S-adenosyl-L-methionine = adenine + epoxyqueuosine(34) in tRNA + H(+) + L-methionine Inhibited by S-adenosylhomocysteine, adenosylornithine and products. tRNA modification; tRNA-queuosine biosynthesis. Monomer. This reaction follows a completely ordered sequential bi-ter kinetic mechanism, with binding of preQ1-tRNATyr followed by AdoMet to form the ternary complex. Products are then released in the following order: adenine, methionine, and oQ-tRNATyr. Belongs to the QueA family.