ubiquitin protein molecule, chemical structure. ubiquitin is a molecular tag that indicates proteins marked for recycling

pdb1ubq amino acid apoptosis atoms biochemical biochemistry biotech biotechnology breakdown chain chemical chemistry crystal structure eukaryotic immunopoietic macromolecule modification molecular molecule nobel prize peptide polymer posttranslational proteasome protein proteolysis proteomics recycling sheet strand tag ubiquitin ubiquitous polypeptide