Puromycin

Puromycin is one of the antibiotics interfering with protein synthesis in the cell by releasing nascent polypeptide chains before their synthesis is completed. This is because it mimicks Aminoacyl-tRNA, which is normally involved. This is in prokaryotes as well as eukaryotes.
A second advantage of its structure is the alpha-amino group, which forms a covalent bond with the carboxyl end, causing dissociation from the ribosome.

     H3C  CH3
       \ /
	N
	|
	C   N
      // \ / \\
      N   C   CH
      |   ||  /
     HC   C--N
      \\  /  |
	N    |
	     |
	  O  |
  HOCH2 /  \ |
      |/    \|
      |\ __ /|
      H |  |
      H-N  OH
	|
	C=O
	|
	C-CH2-benzene ring-OCH3
	|
	NH2

Aminoacyl-tRNA looks the same, but with another side chain at the bottom Carbon atom (aka not the benzene ring).