Protein - Protein Structure

Question 1

Protein Structure: Elements

Answer 1

• Proteins are organic compounds that contain Carbon, Hydrogen, Oxygen and Nitrogen.
• The presence of Nitrogen distinguishes proteins from fats and carbohydrates.

Question 2

Protein Structure: Polypeptides

Answer 2

• Proteins are macromolecular polypeptides —i.e. very large molecules composed of many peptide-bonded amino acids.
• Proteins are formed of a few dozen to several hundred amino acids. The term protein is often used interchangeably with polypeptide.
  Poly = many, peptide = protein

Question 3

Protein Structure: Amino Acids

Answer 3

• Amino acids are the basic building blocks of proteins. Each amino acid contains:
  o An amino group –NH2
  o A carboxylic acid group –COOH
  o A unique side group (R-group) which differentiates amino acids.
• There are approximately 1000 amino acids in nature.
• Not all amino acids are protein building blocks. There are hundreds of ‘non-protein’ or ‘non-proteinogenic amino acids’ that aren’t encoded for in the genetic code, but may have other uses.

Question 4

Protein structure: 3D

Answer 4

• The amino acid chain (the ‘primary structure’) folds in a certain pattern to create its 3D structure.
• This structure is closely linked to the function of the protein (i.e. lock and key).