Describe the geometric features of the common secondary stru

Describe the geometric features of the common secondary structure, the helix. Why is this structure especially common? What are the weak bonds that stabilize the helix?

Solution

Most of the proteins in biological system is in alpha helical structure. This is because of the stability of proteins. a. The side chains are separated .b. The c= o is hydrogen bonded N-H of the peptide link 4 units above. This gives a stable arrangement to the protein. The hydrogen atoms are arranged linearly and hence they are at their maximum strength. In alpha helixes most of the side chains are exposed and they can be available for interaction for better stability. It follows a acceptable and stable value in Ramachandran plot which confirms it nature of maximum stable conformation. All the amino acids have negative phi and psi angles, typical values being -60 degrees and -50 degrees, respectively. Hydrogen bonds are the weaker bonds which interact to form maximum stable molecule.