The amino acid tryptophan. We may finally have an answer to this long standing mystery. The molecular structure of all but one amino acid is an asymmetrical arrangement grouped around carbon.
Life only uses left-handed amino acids and right handed surgars.
Non-biological processes, on the other hand, do not usually distinguish between L and D variants. This step, called chiral selection, is crucial to forming chainlike molecules of pure L amino acids. Hazen and his collaborators performed a simple experiment. Most minerals are centric, that is their structures are not handed. However, some minerals display pairs of crystal surfaces that have a mirror relationship to each other.