How Cells Keep Right-Handed Amino Acids Out

One of the wonders of life at the molecular scale -- a fact that defies chance -- is the purity of left-handed amino acids in proteins. Without this "homochirality," as it is known, proteins would never fold properly into the functional structures that make life possible.

Theoretically, life could be built backwards, using only right-handed amino acids -- as long as the mixture is pure. But the cell's translation machinery (TM) would have to be redesigned to accommodate the change. (Note: l...