BIOS 41 Study Guide - Quiz Guide: Protein Folding, Bovine Spongiform Encephalopathy, Coiled Coil
7 Mar 2017
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Exam 2 study guide: chapter 4: proteins, structure. Link chains of amino acids held together by covalent polypeptide chains. Same sequence in each molecule of the same protein. Tertiary: 3-d form; includes all loops and folds, quaternary, complex of other polypeptides, 2=dimer(heterodimer); 3=trimer; 4=4 tetramer; 6=6 hexamer, etc. X-ray crystallography: proteins crystallized, atoms scatter the x-rays; form a diffraction pattern collected by electron. Shot with x-rays detectors: position and intensity reveal information about the position of each atom. Representations: wire model, positions of the amino acids. Backbone overall organization of the polypeptide chain straightforward way to compare the structures of related proteins. Spacefilling model reveals which amino acids are exposed on the surface shows how the protein might look to a small molecule such as water or to another macromolecule in the cell. Alpha helices: cell membranes, transporters and receptors, rigid cylinder.
