1jk7
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CRYSTAL STRUCTURE OF THE TUMOR-PROMOTER OKADAIC ACID BOUND TO PROTEIN PHOSPHATASE-1
OverviewOverview
Protein phosphatase-1 (PP1) plays a key role in dephosphorylation in, numerous biological processes such as glycogen metabolism, cell cycle, regulation, smooth muscle contraction, and protein synthesis., Microorganisms produce a variety of inhibitors of PP1, which include the, microcystin class of inhibitors and okadaic acid, the latter being the, major cause of diarrhetic shellfish poisoning and a powerful tumor, promoter. We have determined the crystal structure of the molecular, complex of okadaic acid bound to PP1 to a resolution of 1.9 A. This, structure reveals that the acid binds in a hydrophobic groove adjacent to, the active site of the protein and interacts with basic residues within, the active site. Okadaic acid exhibits a cyclic structure, which is, maintained via an intramolecular hydrogen bond. This is reminiscent of, other macrocyclic protein phosphatase inhibitors. The inhibitor-bound, enzyme shows very little conformational change when compared with two, other PP1 structures, except in the inhibitor-sensitive beta12-beta13 loop, region. The selectivity of okadaic acid for protein phosphatases-1 and -2A, but not PP-2B (calcineurin) may be reassessed in light of this study.
About this StructureAbout this Structure
1JK7 is a Single protein structure of sequence from Homo sapiens with MN, SO4, OKA and BME as ligands. Active as Phosphoprotein phosphatase, with EC number 3.1.3.16 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the tumor-promoter okadaic acid bound to protein phosphatase-1., Maynes JT, Bateman KS, Cherney MM, Das AK, Luu HA, Holmes CF, James MN, J Biol Chem. 2001 Nov 23;276(47):44078-82. Epub 2001 Sep 4. PMID:11535607
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