Glycine

Glycine is the simplest of the amino acids, having just a hydrogen in the position of the R group and belonging to the class which has hydrocarbon R-groups. Amino acids of this group are generally hydrophobic, and tend to contribute to closeness in protein folding as they gather together to avoid water.

Glycine as the smallest amino acid is important in the structure of collagen where its small size contributes to the tight winding of collagen fibers into a triple helix form. Collagen contains about 35% glycine, but most proteins contain only a small amount of glycine. Glycine contributes as a signaling molecule (inhibitory neurotransmitter) in the spinal column, brainstem, and retina. (Ahern)

Glycine is important in protein structure where it contributes to the formation of the common alpha helix structure in proteins.

Glycine forms a sweet-tasting colorless crystalline solid.