The primary structure of a protein is the sequence of the amino acids.
A shorthand way of representing primary structure uses three letter abbreviations for amino acids.
The secondary structure is the way in which the peptide chain is folded or coiled in the protein.
Two important secondary structures are α helices and β pleated sheets.
A shorthand way of representing primary structure uses three letter abbreviations for amino acids.
A protein containing alanine, serine and leucine in a portion of its chain would have that portion of the chain represented by Ala-Ser-Leu.
The secondary structure is the way in which the peptide chain is folded or coiled in the protein.
Two important secondary structures are α helices and β pleated sheets.
As shown below these structures are the result of attractive forces known as hydrogen bonds between NH hydrogens and C=O oxygens in the backbone of the polypeptide.
| In the α helix structure: hydrogen bonds are between amino acids in the same chain (usually 5 or 6 amino acid residues apart) . |  | In β pleated sheets: hydrogen bonds are between amino acids in parts of the same chain that lie parallel to one another. |  |