Sandbox Reserved 197: Difference between revisions

Interatomic interactions, delegated by the amino acid sequence, are responsible for formation of a protein's 3D structure [http://en.wikipedia.org/wiki/Protein_folding].  Several of these interactions have been identified by the use of site directed mutagenesis to wildtype RNase A and subsequent comparison of the crystal structure to the wildtype.  

==='''Proline Conformation'''===

Another important role of proline residues is their involvement in β turns. β turns are 180° turns commonly found in globular proteins to allow for a compact structure by connecting the ends of adjacent antiparallel β sheets [http://en.wikipedia.org/wiki/Beta_sheet]. The turn consists of a sequence of four amino acid residues. The carbonyl of the first amino acid hydrogen bonds with the amino group of the fourth amino acid. Proline is involved in β turns because it is small, flexible, and assumes a ''cis'' conformation, all attributes that allow for formation of a turn. In RNase A both Pro93 and Pro114 are involved in β turns.  

==='''Disulfide Bonds'''===