Wobble hypothesis

Wobble hypothesis

This hypothesis was proposed by Francis Crick in 1965

According to this hypothesis, the complete set of 61 sense codons can be read by fewer than 61 distinct tRNAs because pairing properties of the bases in the anticodon. Specifically , the base at the 5’end of the anticodon complementary to the 3’ end of the codon is not constrained three dimensionally as the other 2 bases. This feature allows for less exact base pairing ,so that the base at 5’end of the anticodon can pair with more than one type of base at the 3’end of the codon or it can wobble. No single tRNA molecule can recognize 4 different codons .But if the tRNA molecule contains the modified purine inosine(I) at the 5’end of the anticodon ,then that tRNA can recognize 3 different codons (A,U,C)

G Nucleoside at 5’ end of anticodon   can pair with U or C

C Nucleoside at 5’ end of anticodon   can pair with G

A Nucleoside at 5’ end of anticodon   can pair with U

U  Nucleoside at 5’ end of anticodon   can pair with A or G

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