In proteins, the number and arrangement of individual polypeptides in the final protein molecule.
The level of structural organization in oligomeric proteins (i.e., those composed of more than one subunit) represented by the number and arrangement of the subunits and the interactions between them
The highest level of protein structure, involving a specific aggregation of indivivdual proteins into a larger cluster.
Quaternary structure refers to the association and arrangement of two or more proteins to create a multimeric (more than one subunit) functional unit. Multimerization is often required for the function of the protein subunits within a protein complex. An example is hemoglobin, a protein that has four subunits, two alpha helices and two beta sheets, which are essential for its role as an oxygen carrier. See also Conformation, Primary Structure, Secondary Structure, Structural Biology, Tertiary Structure.
For proteins, there are 4 levels of structure. The first, primary structure, is composed of the amino acid sequence. The secondary structure is how the amino acids next to each other in the sequence are organized. The tertiary structure is the folded 3-D structure of the protein that allows it to perform its functions. The quaternary structure is the total protein structure that is made when all the subunits of the protein are in place.
The arrangement of separate protein chains in a protein molecule with more than one subunit.
the level of structure that results when separate, folded polypeptide chains (subunits) associate in a specific way to produce a complete oligomeric protein.
The structure formed by association of two or more polypeptides.
The highest level of structure found in proteins.
In biochemistry, quaternary structure is the arrangement of multiple folded protein molecules in a multi-subunit complex.
