3ecn

<table><tr><td colspan='2'>[[3ecn]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3ECN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3ECN FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=IBM:3-ISOBUTYL-1-METHYLXANTHINE'>IBM</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[3ecm|3ecm]]</div></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">PDE8A ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/3',5'-cyclic-nucleotide_phosphodiesterase 3',5'-cyclic-nucleotide phosphodiesterase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.4.17 3.1.4.17] </span></td></tr>

[[https://www.uniprot.org/uniprot/PDE8A_HUMAN PDE8A_HUMAN]] Hydrolyzes the second messenger cAMP, which is a key regulator of many important physiological processes. May be involved in maintaining basal levels of the cyclic nucleotide and/or in the cAMP regulation of germ cell development.<ref>PMID:18983167</ref>

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== Publication Abstract from PubMed ==

Cyclic nucleotide phosphodiesterase-8 (PDE8) is a family of cAMP-specific enzymes and plays important roles in many biological processes, including T-cell activation, testosterone production, adrenocortical hyperplasia, and thyroid function. However, no PDE8 selective inhibitors are available for trial treatment of human diseases. Here we report kinetic properties of the highly active PDE8A1 catalytic domain prepared from refolding and its crystal structures in the unliganded and 3-isobutyl-1-methylxanthine (IBMX) bound forms at 1.9 and 2.1 A resolutions, respectively. The PDE8A1 catalytic domain has a K M of 1.8 muM, V max of 6.1 mumol/min/mg, a k cat of 4.0 s (-1) for cAMP, and a K M of 1.6 mM, V max of 2.5 mumol/min/mg, a k cat of 1.6 s (-1) for cGMP, thus indicating that the substrate specificity of PDE8 is dominated by K M. The structure of the PDE8A1 catalytic domain has similar topology as those of other PDE families but contains two extra helices around Asn685-Thr710. Since this fragment is distant from the active site of the enzyme, its impact on the catalysis is unclear. The PDE8A1 catalytic domain is insensitive to the IBMX inhibition (IC 50 = 700 muM). The unfavorable interaction of IBMX in the PDE8A1-IBMX structure suggests an important role of Tyr748 in the inhibitor binding. Indeed, the mutation of Tyr748 to phenylalanine increases the PDE8A1 sensitivity to several nonselective or family selective PDE inhibitors. Thus, the structural and mutagenesis studies provide not only insight into the enzymatic properties but also guidelines for design of PDE8 selective inhibitors.

Kinetic and Structural Studies of Phosphodiesterase-8A and Implication on the Inhibitor Selectivity.,Wang H, Yan Z, Yang S, Cai J, Robinson H, Ke H Biochemistry. 2008 Nov 5. PMID:18983167<ref>PMID:18983167</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 3ecn" style="background-color:#fffaf0;"></div>

[[Category: 3',5'-cyclic-nucleotide phosphodiesterase]]

[[Category: Human]]

[[Category: Cai, J]]

[[Category: Ke, H]]

[[Category: Robinson, H]]

[[Category: Wang, H]]

[[Category: Yan, Z]]

[[Category: Yang, S]]

[[Category: Refolding]]