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6HMM
A enlever quand tout est fini This is a default text for your page '. Click above on edit this page' to modify. Be careful with the < and > signs. You may include any references to papers as in: the use of JSmol in Proteopedia [1] or to the article describing Jmol [2] to the rescue. The 6HMM protein is a humanpoly (ADP-ribose) glycohydrolase. It is an enzyme that will catalyze the hydrolysis of glycosides, here more specifically it will produce a free ADP-ribose. This protein is only present when the DNA is damaged. It influences the damaged chromatin through a derepression on a gene promoter. Consequently this protein is quite interesting for biotechnical applications. Indeed, developing proteins who repair DNA damage is a meaningful goal in research especially in new cancer therapies.
ContentsStructureStructural highlightsThis is a sample scene created with SAT to color by Group, and another to make a transparent representation of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes. Quaternary StructurePoly(ADP-ribose)glycohydrolase interact with PCNA or NUDT5. When this protein is binding with NUDT5 it can remodeling chromatin. Links of PARG with other ligandsFunctionThe protein is a complex composed of the poly (ADP-ribose) glycohydrolase (PARG) and the anthraquinone PDD00013907. The post-translational modifications of the PAR protein (poly ADP-ribose) are important for DNA stability. PDD00013907 is, as already stated, an anthraquinone which is a polycyclic aromatic hydrocarbon usually used in biopesticides as a pest repellant. Here it is considered as a free ligand (of identification number on PDB: 7JB) that can bind to the PARG creating the protein complex 6HMM. Post-translational modifications and anthraquinoneThere are several possible post-translational modifications to stabilize DNA. Most commonly they would be phosphorylation, acetylation or methylation [3]. Another post-translational modification concerning the 6HMM protein is made on the poly(ADP-ribose) protein (PAR). PAR is composed of a repetition of ADP-ribose units linked through glycosidic ribose-ribose bonds [4]. This allows the repair of single-strand breaks on DNA [5]. PARG, a constituent of the 6HMM protein, will degrade PAR to allow the poly (ADP-ribose) polymerase (PARP) to free itself from the damaged, now repaired, site and completes as such reparation [6]. The anthraquinone PDD00013907 is a weakly active and cytotoxic anthraquinone 8a acting as a free ligand binding in the ADP-ribose binding site of the PARG. This PDD00013907 should lead to the inhibition of PARG, which is of interest in the search of novel cancer therapies [6]. The mechanismAs said previously, poly(ADP-ribosylation) is an important post-translational modification for DNA repair. The mechanism behind this repair relies on several factors. At first, the Poly (ADP-ribose) polymerase (PARP), more specifically the subtype PARP1, will recognize and will bind to the single-stranded break on the DNA. It will then autophosphorylate due to NAD+ and form PAR chains. These will then recruit other repair proteins to the site. The role of PARG is the hydrolyzation of the specific ribose-ribose bonds present in PAR which leads to its degradation and as such the reparation cycle will be finished[5]. This degradation is important because without PARG the repair cycle cannot be completed [7] and may lead to cell death. This is partially due to the still present PARP on the previously damaged site maintained by the non-degraded PAR [8]. Diseases and Relevance
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