The ribosome and RPS19. (A) The eukaryotic ribosome consists of ribosomal proteins and ribosomal RNA. The ribosome and its subunits are named by Svedberg units (S), which reflect the particles' sedimentation rate in an ultracentrifuge. The small subunit is named 40S, the large subunit 60S, and the complete ribosome 80S. The 40S subunit is a macromolecule composed by 18S rRNA together with 33 ribosomal proteins of which one is RPS19. (B) RPS19 consists of 144 amino acids because the first methionine is cleaved off. Amino acids predicted to be phosphorylated are labeled with a circled P. The 4 predicted α-helix structures are demonstrated by a green helix. Amino acids that are altered because of missense point mutations in patients with DBA are labeled with red letters. Amino acids mutated in multiple patients are red and underlined. A blue-dotted box marks the point mutation hotspot region.