CAS NE 102 Lecture Notes - Lecture 6: Polyadenylation, Ascl1, Chromatin
20 Jul 2016
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7: from dna to protein how cells read the genome. Controlled protein breakdown helps regulate the amount of each protein in a cell. Hydrolyze (cut) the peptide bonds between amino acids. Proteasomes: large protein machines where proteins are broken down (in both cytosol and nucleus) Proteins are marked for destruction by covalent attachment of a small protein called ubiquitin. Enzymes tag proteins with a short chain of ubiquitin molecules. Protein is unfolded and threaded through proteasome"s central cylinder lined with proteases that chop the protein to pieces. Post-translational modifications: further modifications of proteins once they leave the ribosome. Ex. s: covalent modification (phosphorylation), binding of small-molecule cofactors, association with other protein subunits. Regulates where the protein is found in the cell. Folding allows the newly formed protein to interact with other molecules (proteins, dna, Proteins able to interact because of specific structural conformation and charges within the 2 molecules. Protein degradation also occurs in the lysosome.
