What is a p53 tetramer?

The p53 tumor suppressor protein is a tetramer that binds sequence-specifically to a DNA consensus sequence consisting of two consecutive half-sites, with each half-site being formed by two head-to-head quarter-sites (→← →←).

Does p53 form a tetramer?

In its active conformation, p53 is tetrameric and one domain – the tetramerization domain – permits the oligomerization of this protein.

How p53 binds DNA as a tetramer?

Each p53 subunit binds to one quarter-site, resulting in all four DNA quarter-sites being occupied by one p53 tetramer. The tetramerization domain forms a symmetric dimer of dimers, and two contrasting models have the two DNA-binding domains of each dimer bound to either consecutive or alternating quarter-sites.

What is the main function of p53?

The p53 protein is a key cell cycle regulator that manages the response to stress signals either by inducing cell growth arrest, senescence or apoptosis. The nature and intensity of stress signal, the cell type, and the cellular context dictate the final outcome.

What is a tetramer in biology?

A tetramer (/ˈtɛtrəmər/) (tetra-, “four” + -mer, “parts”) is an oligomer formed from four monomers or subunits. The different sub-units may have each their own activity, such as binding biotin in avidin tetramers, or have a common biological property, such as the allosteric binding of oxygen in hemoglobin.

Is hemoglobin A heterodimer?

Hemoglobin is the protein responsible for carrying oxygen in the blood. It is made up of four polypeptides: two α- and two β-subunits. One α-subunit and one β-subunit will come together to form a heterodimer, and two of these heterodimers will interact to form one hemoglobin molecule.

What is a tetramer in chemistry?

Tetramer: A structure composed of four identical smaller units, or four very similar smaller units. The units may be associated by covalent bonds or by noncovalent forces. This tetrapeptide is Gly-Gly-Gly-Gly, a tetramer composed of four identical amino acid residues (each is a glycine).

What is the role of p53 in apoptosis?

The p53 tumor suppressor acts to integrate multiple stress signals into a series of diverse antiproliferative responses. One of the most important p53 functions is its ability to activate apoptosis, and disruption of this process can promote tumor progression and chemoresistance.

Why is hemoglobin a tetramer?

Hemoglobin is a tetrameric protein that binds and transports four oxygen molecules per unit and then releases them to myoglobin. The binding of oxygen to hemoglobin is allosterically cooperative, in that the binding of each oxygen molecule facilitates the binding of the next.