Why doesn’t a basic side chain (R group) of an amino acid form a peptide bond in protein biosynthesis?

Consider lysine, for example, why can’t its side-chain amino group, –(CH2)4–NH2, form a peptide bond with the carboxyl group of the other amino acid? Is it due to orientation alone are their other properties involved?

  • $\begingroup$ In addition, take a look at transglutaminase and its role in protein cross-linking (including in blood clotting) and the wikipedia entry for the iso-peptide bond. $\endgroup$ – user1136 Feb 8 '18 at 11:30
  • $\begingroup$ Welcome to SE Biology. I have edited your question. Please do not make statements about "nobody being able to tell you something". It is untrue, irrelevant and appears to be an attempt to draw attention to your question. If nobody is able to tell you I suggest you try to find out for yourself. If you read the Help on asking questions you will see you should show your research when posting. Do you know about protein synthesis on ribosomes and their peptidyl transferase activity? Research this first and then ask for help if you still need it. $\endgroup$ – David Feb 8 '18 at 11:52
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    $\begingroup$ Possible duplicate of Why don't amino acids get linked in the functional groups of acidic and basic amino acids? $\endgroup$ – Guillaume Feb 12 '18 at 17:36