Dear all
I have a somewhat philosophical question. Why do all protein sequences start with a methionine (not referring to mature/processed form)? What is so special about methionine and cannot be replaced by other amino acids?
Second, how does the ribosome know the first start codon is for methionine when the codon is not AUG? This is about the alternative start codons like GUG.
Thank you.
Theresa
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