Protein Structure
Certain proteins possess a fourth level of structural organisation called a quaternary structure.
Quaternary structures are found in proteins that consist of more than one polypeptide chain linked together.
Alternatively, proteins may have a quaternary structure if they include inorganic prosthetic groups as part of their structure.
Not all proteins will have a quaternary structure – many proteins consist of a single polypeptide chain.
Certain proteins possess a fourth level of structural organisation called a quaternary structure.
Quaternary structures are found in proteins that consist of more than one polypeptide chain linked together.
Alternatively, proteins may have a quaternary structure if they include inorganic prosthetic groups as part of their structure.
Not all proteins will have a quaternary structure – many proteins consist of a single polypeptide chain.
Quaternary Structure
An example of a protein with a quaternary structure is haemoglobin (O2 carrying molecule in red blood cells)
- Haemoglobin is composed of four polypeptide chains (two alpha chains and two beta chains)
- It is also composed of iron-containing haeme groups (prosthetic groups responsible for binding oxygen)