- Other bond type in protein structure
Acidic and basic R group exist in an ionized state at certain IH. Acidic R group are negatively change while basic R group are + charge. They can this be attracted to each other forming ionic bonds.
- Disulphide bond
The amino acid cysteine contain a sulphydryl group (-SH) in it R group. If two molecules of cysteine are lined up along side which each other, neighboring sulphydryl group can be oxidize to form a disulphide bond, disulphide bonds may be form bin different part of the same chain or bin chains of amino acid.e.g insulin. When disulphide bonds are form bin different part of the same chain, the can make the molecule to fold into a particular shape. They are strong and not easily broken.
- Hydrogen interactions
When hydrogen is linked to a highly electronegative element, it becomes slidly positively charge. This because the electrons that are shared and which are negatively charged are attracted more toward the electronegative element e.g. O2 andN2. Hydrogen may attracted toward a neighboring electronegative element such O2 of C=O group or nitrogen of NH group. C=O and NH group occur along the length of a poly peptide chain and can interact to produce regular shapes such as –helix. The bond is weak but as it occurrence is frequent, the total effect makes the considerable contribution towards molecular stability as in the structure of –helix.
- Hydrophobic interactions
Some R groups are non-polar and therefore hydrophilic such as those of the amino acid, thyrosine and valine. If a polypeptide chains contains a numbers of these groups and is an aqueous environnement, his chain will tend to fold so that a maximum number of hydrophobic groups comes into close contact and exclude water. This is how many globular proteins fold up. There hydrophobic groups lend to point in word toward the center of the roughly spherical molecule while they hydrophilic groups face out word into the aqeous envent making the proteins soluable
