BIOC12H3 Lecture 4: BIOC12FAll2012 Lecture Week 4 Notes
Document Summary
2012 lecture week 4: structure of proteins (chapter 6) Bioc12fall2012 lecture week 4: structure of proteins (chapter 6) Human hemoglobin and its 3d structure: human hemoglobin contains 4 polypeptide chains (subunits): 2 alpha and 2 beta chains the sequence in part a is a fragment from the b-chain. Different ways to view 3d structures: space filling model: Each atom is shown as a solid sphere. It shows the overall shape of the protein and the surface exposed to the aquous solvent. Ball-and-stick model: excellent for showing bonding arrangement. Backbone model: shows general course of the polypeptide chain difficult to see secondary structures, only shows the bonded (amide bonds) backbone. Non-covalent interactions stabilize the higher levels of protein structure. Secondary, tertiary and quaternary structure of proteins is formed and stabilized by weak forces. Electrostatic interactions = ionic interactions : occurs between 2 charged atoms. Example: between lysine and glutamate in irak-4 which is an enzyme that phosphorylates other proteins.
