BCH 261 Lecture Notes - Lecture 8: Gene Duplication, Ubiquitin, Threonine
7 Mar 2017
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Document Summary
Proteins can be modified covalently or non-covalently by prosthetic groups: Phosphoproteins: serine, threonine and tyrosine residues modified with a phosphate (r groups with -oh) Ubiquitination: lysine residues are modified by ubiquitin, a small protein that targets for proteins for degradation. Disulphide bonds: oxidation between -sh groups of two cysteines. Association with small organic molecules (heme, falvin) Proteins with similar structure and functions can have similar primary structure. When 2 proteins have similar primary sequences, these can be one of the following. Homologue (homolog): a gene related to another gene from a different species by evolving from a common ancestor. Orthologue (ortholog): gene related to another gene from a different species by evolving from a common ancestor (homologue) and, has a similar function in each organism. Paralogue (paralog): a gene related to another gene by gene duplication in the same organism. Separation relies on differences in physico-chemical properties: charge, size, affinity for a ligand, solubility, hydrophobicity, thermal stability.
