Find a protein using PDB explorer–describe your protein, including what disease state or other real-world application it has. p53 (protein 53 or tumor protein 53)     p53 is a tumor suppressor protein encoded by the TP53 gene. p53 is crucial in many multicellular organisms for its function of regulation of the cell cycle by preventing cells from growing & dividing too fast or uncontrollably, which works as a tumor suppressor. The name p53 refers to its molecular mass which is 53-kilodalton (kDa). p53 tumor suppressor is a flexible molecule composed of 4 identical protein chains. For its role in preserving stability and preventing genome mutation, p53 has been described as "the guardian of the genome".    The cellular DNA faces many dangers including chemicals, viruses, radiation, and UV rays. p53 binds directly to DNA at chromosome 17 in humans. p53 serves a critical role in determining whether the DNA will be repaired, or the damaged cell will undergo apoptosis (self-destruction). If the DNA can be repaired, p53 activated genes which trigger DNA repairing proteins. p53 also arrests growth by holding the cell in the G1/S regulation point of its cell cycle. By holding its at this point, it allows the DNA repair proteins to fix the damage and continue its cell cycle. If the DNA cannot be repaired p53 suppresses cell division and signals for apoptosis. This prevents cells with mutated or damaged DNA from dividing, and prevents tumor development.    p53 has a central role in protecting your body from cancer. Cancer cells use two methods of mutations. They either cause uncontrolled growth and multiplication, or block the normal defense that protect against unnatural growth. Cancer changes the p53 protein and the TP53 gene by causing missense mutations that allow the cell to build with a p53 error. In this mutant the p53 is blocked and causes multiplication and uncontrolled growth, and the cell develops a tumor.