MCD BIO 165A Lecture Notes - Lecture 15: Protein Folding, Proteasome, Multiprotein Complex
15 Dec 2016
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Eliminate abnormal proteins, indiv cellular proteins, misfolded exported proteins, tfs. Present in nucleus and cytosol: allows rapid tf destruction, allow cell to change fate. Uses atp: drives conformational change, recognizes substrate protein and unfolds it, open/closes proteasome gate, not involved in protein cleavage. Regulatory particle = rp = cap: made of several diff proteins, usually atpases - cleave atp. Some recognize ub: composed of several diff proteins. Core particle = cp: 2 copies of each 14 diff proteins, 7 proteins = group = ring. Beta: proteolytic enzymes, degradation active site face inside. Tf: cyclins, proteins encoded by viruses/intracellular parasites, contribute to defense, direct destruction, generate antibodies, misfolded proteins. In animals: produces short peptides which induce antibody generation. Ub can be added to other proteins by conjugation onto lysine. Ubiquitin ligases add ubiquitin to lysine: post translational, many diff types. E1, e2, e3: responsible for addition of ub. E3 ligases: provide specificity of protein recognition, binds to the protein.
