A major activity in living cells is the manufacture of new proteins. For this purpose cells utilize hundreds of ribosomes that read genetic material and according to the genetic sequence synthesize new protein (See also Managing the Protein Assembly Line, Born to Control, Shutting Down the Protein Factory). This crucial synthesis is highly controlled, in particular, in regard to avoidance of errors. For example, proteins of all living systems are made solely of so-called L-amino acids and not the closely related D-amino acids, L- and D-amnio acids being related like left and right hand. Life could have emerged from either "left-handed" or "right-handed" amino acids, but in living cells on Earth, protein synthesis occurs exclusively with L-amino acids, despite of the fact that D-amino acids are actually abundant in organisms and there are neither geometric nor energetic reasons preventing D-amino acid incorporation. For example, D-Serine in the human central nervous systems are present at very high concentrations in vivo. So, the ribosome must have developed early on in evolution mechanisms that prevent incorporation of D-amino acids into nascent proteins. In a recent report, experimental and computational biologists reported their discovery how the ribosome readily discriminates between L- and D-amino acids within its catalytic center. Read more on our Ribosome website.