queuosine ( q ) , 7- [ ( 4,5-cis-dihydroxy-2-cyclopentene-1-yl ) -amino ) methyl ) -7- deazaguanosine , and q derivatives usually replace guanosine in the anticodon of trnas ( gun ) of eubacteria and of cytoplasmic and mitochondrial trnas of lower and higher eucaryotes except yeasts .
C0028619
queuosine
C0018330
guanosine