Protomer

Protein complex involved in signal transduction

A protomer is a fundamental unit of a protein complex that can assemble with other protomers to form a larger oligomeric protein structure. Protomers are essential in the formation of quaternary structures of proteins, which are crucial for their biological function.

Structure

Protomers are typically composed of one or more polypeptide chains that fold into a specific three-dimensional structure. The arrangement of these chains allows protomers to interact with each other through various types of protein-protein interactions, such as hydrogen bonds, ionic bonds, and hydrophobic interactions.

Function

Protomers play a critical role in the function of many enzymes, receptors, and other protein complexes. By assembling into larger structures, protomers can create active sites, binding sites, or channels that are necessary for the protein's activity. For example, the hemoglobin molecule is composed of four protomers, each of which binds to an oxygen molecule, allowing for efficient oxygen transport in the blood.

Examples

• Hemoglobin: Composed of four protomers (two alpha and two beta chains).
• ATP synthase: A complex enzyme that synthesizes ATP from ADP and inorganic phosphate.
• Ion channels: Many ion channels are formed by the assembly of multiple protomers, creating a pore through which ions can pass.

Assembly

The assembly of protomers into larger complexes is a highly regulated process that can be influenced by various factors, including post-translational modifications, ligand binding, and changes in the cellular environment. Misassembly or malfunction of protomer complexes can lead to various diseases, including neurodegenerative disorders and cancer.

Related Pages

• Protein structure
• Quaternary structure
• Oligomeric protein
• Protein-protein interaction
• Enzyme
• Receptor (biochemistry)
• Ion channel