BCH 4024 Lecture 5: L5

• School: University of Florida
• Department: Biochemistry and Molecular Biology
• Course: BCH 4024
• Professor: Daniel L Purich

Document Summary

Range in molecular weight from 5,000 > 1,000,000. These polypeptides fold to form compact 3-d structures that are required for biological activity. Some proteins are structureless, but gain regular 3-d structure, but after binding to a well folded protein. Protein structure is conceptualized at 4 hierarchical levels. Not a time ordered sequence of folding process. It all begins with the peptide bond. Pauling and corey analyzed geometry and dimensions of peptide bonds in crystal structures of simple molecules containing one or several peptide bonds. They obtained consensus bond-lengths and bond angles. C-n peptide bond length is consistently shorter than the c-n bond in most amides. Planarity of peptide bond is key to life. Analyzing the the geometry and dimensions of simple molecules containing one or several peptide bonds, pauling & corey discovered: 1. 32 a for peptide vs 1. 53 a for simple amides. C=o and n-h atoms within the peptide bond are approximately coplanar.