What does the AUG start codon specify in prokaryotes?

In prokaryotes, the AUG start codon specifies formyl-methionine. This is an important distinction because, while nucleotides that constitute the AUG codon signal the beginning of protein synthesis, the specific amino acid that is incorporated at this position in prokaryotic proteins is not the standard methionine found in eukaryotes.

During the initiation of protein synthesis in prokaryotes, the ribosome recognizes the AUG start codon and recruits a special initiator tRNA that is charged with formyl-methionine, rather than methionine itself. The formyl group is subsequently removed after the polypeptide chain is synthesized. This process is crucial for the formation of proteins in bacteria and archaea, and it reflects how the mechanisms of translation can vary between different domains of life.

The other options, such as methionine, serine, and cysteine, do not accurately represent what the AUG codon specifies in the context of prokaryotic translation initiation. Instead, they may be involved in other aspects of protein synthesis or refer to different codons altogether in the genetic code. Thus, understanding that prokaryotic translation initiates with formyl-methionine when the AUG