Although amino acids are often shown in textbooks as the right-hand structure, they actually mostly exist as ... and selenocysteine, a cysteine analogue only found in some lineages, are included in ...

A cocrystal structure ... for this '21 st amino acid'. The structure resolves some mechanistic questions and allows for comparison of the tRNA-dependent synthesis of cysteine and selenocysteine.

They play a crucial role in the structure, function ... The eleven non-essential amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, ...