CHEM 451 Study Guide - Final Guide: Total Internal Reflection, Total Internal Reflection Fluorescence Microscope, Entropy
Document Summary
3 x left handed protein helices --h bond--> right handed triple helix/ fibre. Xyg triplet sequence (glycine conserved across organisms, x = proline, y = hydroxyproline in vertebrates) Every 3 a. a -> glycine (so glycine are aligned) 3 staggered strands, glycine never interacts with other glycine. Pro = rigid/ limits assembly of monomers so less entropic cost, gly = diff conformation from all the other proteins. Locking rotation makes 3 strands have less conformation -> less entropic decrease/ more stable triple helix. H2o h bonds with collagen, but never inside the chain/ on surface of structure. > arg side chain can h bond with collagen. Modifying gly would break triple helix, so chenoweth made gly with n that replaced c (backbone modification) > n can form h bond with o. > confirmed h bond with x ray crystallography - conserved old h bonds too.
