2J8Z

Crystal Structure of human P53 inducible oxidoreductase (TP53I3,PIG3)

Summary for 2J8Z

• Entry DOI: 10.2210/pdb2j8z/pdb
• Related: 2OBY
• Descriptor: QUINONE OXIDOREDUCTASE, NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE (3 entities in total)
• Functional Keywords: medium-chain dehydrogenase- reductases, oxidoreductase, quinone oxidoreductase, oxidative stress response
• Biological source: HOMO SAPIENS (HUMAN)
• Total number of polymer chains: 1
• Total formula weight: 38874.17

Authors

Pike, A.C.W.,Shafqat, N.,Debreczeni, J.,Johansson, C.,Haroniti, A.,Gileadi, O.,Arrowsmith, C.H.,Edwards, A.,Weigelt, J.,Sundstrom, M.,von Delft, F.,Porte, S.,Fita, I.,Pares, J.,Pares, X.,Oppermann, U. (deposition date: 2006-10-31, release date: 2006-11-06, Last modification date: 2023-12-13)

Primary citation

Porte, S.,Valencia, E.,Yakovtseva, E.A.,Borras, E.,Shafqat, N.,Debreczeny, J.E.,Pike, A.C.W.,Oppermann, U.,Farres, J.,Fita, I.,Pares, X.
Three-Dimensional Structure and Enzymatic Function of Proapoptotic Human P53-Inducible Quinone Oxidoreductase Pig3.
J.Biol.Chem., 284:17194-, 2009

PubMed Abstract: Tumor suppressor p53 regulates the expression of p53-induced genes (PIG) that trigger apoptosis. PIG3 or TP53I3 is the only known member of the medium chain dehydrogenase/reductase superfamily induced by p53 and is used as a proapoptotic marker. Although the participation of PIG3 in the apoptotic pathway is proven, the protein and its mechanism of action were never characterized. We analyzed human PIG3 enzymatic function and found NADPH-dependent reductase activity with ortho-quinones, which is consistent with the classification of PIG3 in the quinone oxidoreductase family. However, the activity is much lower than that of zeta-crystallin, a better known quinone oxidoreductase. In addition, we report the crystallographic structure of PIG3, which allowed the identification of substrate- and cofactor-binding sites, with residues fully conserved from bacteria to human. Tyr-59 in zeta-crystallin (Tyr-51 in PIG3) was suggested to participate in the catalysis of quinone reduction. However, kinetics of Tyr/Phe and Tyr/Ala mutants of both enzymes demonstrated that the active site Tyr is not catalytic but may participate in substrate binding, consistent with a mechanism based on propinquity effects. It has been proposed that PIG3 contribution to apoptosis would be through oxidative stress generation. We found that in vitro activity and in vivo overexpression of PIG3 accumulate reactive oxygen species. Accordingly, an inactive PIG3 mutant (S151V) did not produce reactive oxygen species in cells, indicating that enzymatically active protein is necessary for this function. This supports that PIG3 action is through oxidative stress produced by its enzymatic activity and provides essential knowledge for eventual control of apoptosis.

PubMed: 19349281
DOI: 10.1074/JBC.M109.001800

Experimental method

X-RAY DIFFRACTION (2.5 Å)