Question

For each of the following sequences, rank them in order (from best to worst) as sequences that could be used to initiate translation according to Kozak's rules. GACGCCAUGG GCCUCCAUGC GCCAUCAAGG GCCACCAUGG

Short answer

The ranking, in order from best to worst, of the sequences for initiating translation according to Kozak's rules is: Sequence 4 > Sequence 1 > Sequence 2 > Sequence 3.

Step-by-step solution

Identifying the Sequences

Identify the 4 sequences given in the problem: Sequence 1: GACGCCAUGG. Sequence 2: GCCUCCAUGC. Sequence 3: GCCAUCAAGG. Sequence 4: GCCACCAUGG.

Comparing Each Sequence to Kozak's Consensus

Compare each sequence with the Kozak's consensus sequence: Sequence 1: Presence of GCC prior to AUG and G after AUG. Sequence 2: GCC prior to AUG but absence of G after AUG. Sequence 3: Presence of GCC prior to AUG, but wrong start codon AUC instead of AUG, and presence of G after the start codon. Sequence 4: Presence of GCC prior to AUG and G after AUG.

Ranking the Sequences

Rank the sequences based on their accordance to the Kozak's consensus sequence. The sequences should be ranked by their ability to initiate translation, which is directly proportional to how closely they follow Kozak's consensus sequence. Sequence 4: Follows the consensus sequence closely and therefore expected to be the strongest initiator of translation. Sequence 1: Despite a slight difference from the consensus sequence at the -3 position, it follows closely and should be the second strongest in initiating translation. Sequence 2: Has a significant difference at the +4 position, and therefore should rank third in effectiveness to initiate translation. Sequence 3: Starts with the wrong start codon, and therefore is not a valid initiator of translation.