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==Structural basis of reactivation of oncogenic p53 mutants by a small molecule: methylene quinuclidinone (MQ). Human p53DBD-R273C/S240R double mutant bound to DNA and MQ: R273C/S240R-DNA-MQ==
<StructureSection load='7b4d' size='340' side='right'caption='[[7b4d]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7b4d]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7B4D OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7B4D FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.85&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FMT:FORMIC+ACID'>FMT</scene>, <scene name='pdbligand=QN8:(2~{R})-2-methyl-1-azabicyclo[2.2.2]octan-3-one'>QN8</scene>, <scene name='pdbligand=QNN:(2~{S})-2-methyl-1-azabicyclo[2.2.2]octan-3-one'>QNN</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=7b4d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7b4d OCA], [https://pdbe.org/7b4d PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7b4d RCSB], [https://www.ebi.ac.uk/pdbsum/7b4d PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7b4d ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/P53_HUMAN P53_HUMAN] Note=TP53 is found in increased amounts in a wide variety of transformed cells. TP53 is frequently mutated or inactivated in about 60% of cancers. TP53 defects are found in Barrett metaplasia a condition in which the normally stratified squamous epithelium of the lower esophagus is replaced by a metaplastic columnar epithelium. The condition develops as a complication in approximately 10% of patients with chronic gastroesophageal reflux disease and predisposes to the development of esophageal adenocarcinoma.  Defects in TP53 are a cause of esophageal cancer (ESCR) [MIM:[https://omim.org/entry/133239 133239].  Defects in TP53 are a cause of Li-Fraumeni syndrome (LFS) [MIM:[https://omim.org/entry/151623 151623]. LFS is an autosomal dominant familial cancer syndrome that in its classic form is defined by the existence of a proband affected by a sarcoma before 45 years with a first degree relative affected by any tumor before 45 years and another first degree relative with any tumor before 45 years or a sarcoma at any age. Other clinical definitions for LFS have been proposed (PubMed:8118819 and PubMed:8718514) and called Li-Fraumeni like syndrome (LFL). In these families affected relatives develop a diverse set of malignancies at unusually early ages. Four types of cancers account for 80% of tumors occurring in TP53 germline mutation carriers: breast cancers, soft tissue and bone sarcomas, brain tumors (astrocytomas) and adrenocortical carcinomas. Less frequent tumors include choroid plexus carcinoma or papilloma before the age of 15, rhabdomyosarcoma before the age of 5, leukemia, Wilms tumor, malignant phyllodes tumor, colorectal and gastric cancers.<ref>PMID:10570149</ref> <ref>PMID:1933902</ref> <ref>PMID:1978757</ref> <ref>PMID:2259385</ref> <ref>PMID:1737852</ref> <ref>PMID:1565144</ref> <ref>PMID:7887414</ref> <ref>PMID:8825920</ref> <ref>PMID:9452042</ref> <ref>PMID:10484981</ref>   Defects in TP53 are involved in head and neck squamous cell carcinomas (HNSCC) [MIM:[https://omim.org/entry/275355 275355]; also known as squamous cell carcinoma of the head and neck.  Defects in TP53 are a cause of lung cancer (LNCR) [MIM:[https://omim.org/entry/211980 211980]. LNCR is a common malignancy affecting tissues of the lung. The most common form of lung cancer is non-small cell lung cancer (NSCLC) that can be divided into 3 major histologic subtypes: squamous cell carcinoma, adenocarcinoma, and large cell lung cancer. NSCLC is often diagnosed at an advanced stage and has a poor prognosis.  Defects in TP53 are a cause of choroid plexus papilloma (CPLPA) [MIM:[https://omim.org/entry/260500 260500]. Choroid plexus papilloma is a slow-growing benign tumor of the choroid plexus that often invades the leptomeninges. In children it is usually in a lateral ventricle but in adults it is more often in the fourth ventricle. Hydrocephalus is common, either from obstruction or from tumor secretion of cerebrospinal fluid. If it undergoes malignant transformation it is called a choroid plexus carcinoma. Primary choroid plexus tumors are rare and usually occur in early childhood.<ref>PMID:12085209</ref>   Defects in TP53 are a cause of adrenocortical carcinoma (ADCC) [MIM:[https://omim.org/entry/202300 202300]. ADCC is a rare childhood tumor of the adrenal cortex. It occurs with increased frequency in patients with the Beckwith-Wiedemann syndrome and is a component tumor in Li-Fraumeni syndrome.<ref>PMID:11481490</ref>   Defects in TP53 are the cause of susceptibility to basal cell carcinoma 7 (BCC7) [MIM:[https://omim.org/entry/614740 614740]. A common malignant skin neoplasm that typically appears on hair-bearing skin, most commonly on sun-exposed areas. It is slow growing and rarely metastasizes, but has potentialities for local invasion and destruction. It usually develops as a flat, firm, pale area that is small, raised, pink or red, translucent, shiny, and waxy, and the area may bleed following minor injury. Tumor size can vary from a few millimeters to several centimeters in diameter.<ref>PMID:21946351</ref> 
== Function ==
[https://www.uniprot.org/uniprot/P53_HUMAN P53_HUMAN] Acts as a tumor suppressor in many tumor types; induces growth arrest or apoptosis depending on the physiological circumstances and cell type. Involved in cell cycle regulation as a trans-activator that acts to negatively regulate cell division by controlling a set of genes required for this process. One of the activated genes is an inhibitor of cyclin-dependent kinases. Apoptosis induction seems to be mediated either by stimulation of BAX and FAS antigen expression, or by repression of Bcl-2 expression. In cooperation with mitochondrial PPIF is involved in activating oxidative stress-induced necrosis; te function is largely independent of transcription. Induces the transcription of long intergenic non-coding RNA p21 (lincRNA-p21) and lincRNA-Mkln1. LincRNA-p21 participates in TP53-dependent transcriptional repression leading to apoptosis and seem to have to effect on cell-cycle regulation. Implicated in Notch signaling cross-over. Prevents CDK7 kinase activity when associated to CAK complex in response to DNA damage, thus stopping cell cycle progression. Isoform 2 enhances the transactivation activity of isoform 1 from some but not all TP53-inducible promoters. Isoform 4 suppresses transactivation activity and impairs growth suppression mediated by isoform 1. Isoform 7 inhibits isoform 1-mediated apoptosis.<ref>PMID:9840937</ref> <ref>PMID:11025664</ref> <ref>PMID:12810724</ref> <ref>PMID:15186775</ref> <ref>PMID:15340061</ref> <ref>PMID:17317671</ref> <ref>PMID:17349958</ref> <ref>PMID:19556538</ref> <ref>PMID:20673990</ref> <ref>PMID:20959462</ref> <ref>PMID:22726440</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In response to genotoxic stress, the tumor suppressor p53 acts as a transcription factor by regulating the expression of genes critical for cancer prevention. Mutations in the gene encoding p53 are associated with cancer development. PRIMA-1 and eprenetapopt (APR-246/PRIMA-1(MET)) are small molecules that are converted into the biologically active compound, methylene quinuclidinone (MQ), shown to reactivate mutant p53 by binding covalently to cysteine residues. Here, we investigate the structural basis of mutant p53 reactivation by MQ based on a series of high-resolution crystal structures of cancer-related and wild-type p53 core domains bound to MQ in their free state and in complexes with their DNA response elements. Our data demonstrate that MQ binds to several cysteine residues located at the surface of the core domain. The structures reveal a large diversity in MQ interaction modes that stabilize p53 and its complexes with DNA, leading to a common global effect that is pertinent to the restoration of non-functional p53 proteins.

Structural basis of reactivation of oncogenic p53 mutants by a small molecule: methylene quinuclidinone (MQ).,Degtjarik O, Golovenko D, Diskin-Posner Y, Abrahmsen L, Rozenberg H, Shakked Z Nat Commun. 2021 Dec 3;12(1):7057. doi: 10.1038/s41467-021-27142-6. PMID:34862374<ref>PMID:34862374</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7b4d" style="background-color:#fffaf0;"></div>

==See Also==
*[[P53 3D structures|P53 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Degtjarik O]]
[[Category: Diskin-Posner Y]]
[[Category: Rozenberg H]]
[[Category: Shakked Z]]