Proteins have varying levels of structure in the body. These levels vary depending on the type of protein (i.e., the amino acid sequence of the protein that defines its function), the maturity of the protein, and even the medium in which the protein resides.

Thus, there are four levels of structure.

The first structure corresponds to the amino acid sequence of the protein.

The second structure is related to the first stage of protein compaction, where two structures are observed: alpha (alpha) helix and beta (beta) fold.

The third structure corresponds to the compression of the secondary structure in between.

The fourth structure is characterized by the assembly of several protein subunits (each exhibiting a tertiary structure) between them. The most suitable example is hemoglobin.