W OBBLE P ROBLEMS WOBBLE RULES for codon-anticodon pairing Simple rules govern pairing between a codon (in mRNA) and the anti-codon (in tRNA). 1. As for all nucleic acids, pairing is antiparallel ---- a 5’ to 3’ sequence in the codon pairs with a complement (in the anticodon) aligned 3’ to 5’. 2. As for all nucleic acids, a purine always pairs with a pyrimidine and Adenine pairs with Uracil (Thymine in DNA) Guanine pairs with Cytosine. 3. The only novelty is that for tRNA/codon pairing G-U pairs (and U-G pairs) are permitted in the third position (3’ end) of the codon. That is, the anti-codon 3’ GUG 5’ can pair with codon 5’ CAU 3’ as well as 5’ CAC 3’ (G in anticodon reads both U and C in codon) but the anti-codon 3’ GUA 5’ can pair only with codon 5’ CAU 3’ (A in anticodon can’t wobble -- reads only U) Notice, there is no anticodon that can pair uniquely with codon 5’ CAC 3’.
This is the end of the preview. Sign up
access the rest of the document.