CHEM 451 Lecture Notes - Lecture 5: Circular Dichroism, Alpha Helix, N-Terminus
Document Summary
Circular dichroism = spectroscopic approach looking at protein secondary structure, used to look at protein stability. Used when you purify a protein and you can test it on cd. Solution technique, put protein in buffer and run spectrum. Secondary structure defined by peptide backbone, so we are most interested in the black, red, green. Alpha helix = -ve peaks at 208, 222. When helicity is lost -> protein unfolded, takes on disordered (green state) -> big loss at 222. 222 (alpha helix) , 215- 217 (beta sheet) = when there"s loss/ gain of elements. Slide 7 stability of alpha helix: end capping. N cap and c cap = first and last residue in the helix, formally defined by h bonding ability. C cap = last one to have h bond with ___ 4 before it. N and c cap is first and last, and n1, n2, n3, residues that immediately flank ____
