The Protein Structure
The basic structure common to all proteins is the peptide linkage which is formed by condensation the carboxyl group of one of amino acid with the amino group of another.
In this way chains are created, which contains only 3 amino acids, to complex polymers of 1000 or more.
The sequence in which amino acids are arranged in the peptide chain is known as the primary structure of the molecule.
The proper sequence of amino acids tends to be a critical factor in protein function.
In some heritable disease, such as sickle cell anemia, the defect is due to the genetic substitution of only one amino acid in the hemoglobin molecule.
Differences in sequence of three amino acids in insulin from different species, however, do not affect the activity of the hormone apparently, because this three amino acid sequence is not an active site of the molecule.
Biological activity of a protein, however, depends not only on the sequence of the amino acids but also on the spatial arrangement of the long peptide chain.
Although the peptide bond is the primary and also the strongest linkage ion the protein polymer, other peptides of bonding occur.
These additional linkages or secondary bonds are partly responsible or the arrangement of the molecule.
The Protein Structure
