Levels of protein structure.

Authors Avatar

Levels of Protein Structure

Proteins are a group of organic compounds whose molecules consist of carbon, oxygen, nitrogen and sometimes sulphur atoms. They are condensation polymers of amino acids. Each amino acid carries two functional groups ( an amino group – NH and a carboxyl group – COOH.)  These two functional groups are attached to a alpha-carbon along with hydrogen and the ‘R’ group. The ‘R’ group differs from amino acid to amino acid.

Amino acids can be joined together by condensation. A hydrogen atom is removed from the amino group of one amino acid and this combines with an – OH group removed from the carboxylic acid of the other, forming a molecule of water. This is called a dipeptide bond. Longer chains are called polypeptides. The shape and the properties of the polypeptides are determined by the order of the ‘R’ group. The varying of the ‘R’ group and the arrangements of the other amino acids makes it possible to form an infinite number of different polypeptides. A protein consists of one or more of these polypeptide chains folded into a complex 3D shape. Different proteins have different structures.

Join now!

The first structure is called the primary structure. The primary structure of a protein is a linear sequence of amino acids in its molecule (It is the specific sequence of amino acids in a polypeptide). This structure is found in all proteins and it involves peptide bonds.

The Secondary structure of proteins involves polypeptide chains folding or twisting in various ways. The most common ways are to coil to form a helix (alpha-helix) or to fold into sheets (beta pleated sheet). The secondary structure of proteins occurs due to the formation of hydrogen bond in the polypeptide. It ...

This is a preview of the whole essay