#Polypeptide backbone series#

The properties of amino acids also influence the tertiary structure or overall shape of the protein. The polar and charged amino acids are hydrophilic and can dissolve in water, whereas the nonpolar amino acids are hydrophobic and do not dissolve in water. They can be polar, nonpolar, or charged, and this gives rise to amino acids with varying physical properties. The side chains of amino acids are often called R groups. While the secondary structure is formed by interactions between the backbone constituents, the tertiary structure is the overall three-dimensional shape that is formed by the interactions of the side chains of the various amino acids. Quaternary structure is the association between two or more polypeptides, but not every protein has a quaternary structure. Tertiary structure is the three-dimensional shape of the protein determined by regions stabilized by interactions between the side chains. Secondary structure is comprised of regions stabilized by hydrogen bonds between atoms in the polypeptide backbone. In brief, primary structure is the linear chain of amino acids. Every protein can be described according to its primary structure, secondary structure, tertiary structure, and quaternary structure is present. By forming peptide bonds between the amino and carboxyl groups on two different amino acids, large polypeptide chains can be created. As diverse as they can be, they are all made up of the same 20 amino acids. They are known as the most structurally complicated biological molecules. Each of these proteins has its structure and function. A human has tens of thousands of proteins in their body at any given moment in time. Different proteins can play a role in speeding up chemical reactions, storage, defense, cell communication, movement, and structural support. There are many different types of proteins. They account for 50% of the dry mass of cells and play a role in everything an organism does. (1994) 19: 135-8.Nearly every function in living beings depends on proteins. Richardson (1992) Protein Science 1: 3-9. Reference: 'THE KINEMAGE: A TOOL FOR SCIENTIFIC COMMUNICATION' D.C. Kinemages were originally implemented under the auspices of the Innovative Technology Fund and the Protein Society, and the programming and maintenance are done by David C. These 'kinemages' (kinetic images) can be rotated, moved, and zoomed, and parts can be hidden or shown. This module includes links to KiNG (Kinemage, Next Generation), which displays three-dimensional structures in an animated, interactive format. As you traverse though this module please note these aspects. We also view structures in lots of ways - Cα backbone, ball-and-stick, CPK, ribbon, spacefilling - as well color is used to highlight different aspects of the amino acids, structure, etc.

#Polypeptide backbone series#

In this series of pages we examine the different levels of protein organization. A protein's primary structure is defined as the amino acid sequence of its polypeptide chain secondary structure is the local spatial arrangement of a polypeptide's backbone (main chain) atoms tertiary structure refers to the three-dimensional structure of an entire polypeptide chain and quaternary structure is the three-dimensional arrangement of the subunits in a multisubunit protein.