1u32
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /> <applet load="1u32" size="450" color="white" frame="true" align="right" spinBox="true" caption="1u32, resolution 2.00Å" /> '''Crystal structure o...)
Next diff →
Revision as of 17:24, 12 November 2007
|
Crystal structure of a Protein Phosphatase-1: Calcineurin Hybrid Bound to Okadaic Acid
Overview
Protein phosphatase-1 and protein phosphatase-2B (calcineurin) are, eukaryotic serine/threonine phosphatases that share 40% sequence identity, in their catalytic subunits. Despite the similarities in sequence, these, phosphatases are widely divergent when it comes to inhibition by natural, product toxins, such as microcystin-LR and okadaic acid. The most, prominent region of non-conserved sequence between these phosphatases, corresponds to the beta12-beta13 loop of protein phosphatase-1, and the L7, loop of toxin-resistant calcineurin. In the present study, mutagenesis of, residues 273-277 of the beta12-beta13 loop of the protein phosphatase-1, catalytic subunit (PP-1c) to the corresponding residues in calcineurin, (312-316), resulted in a chimeric mutant that showed a decrease in, sensitivity to microcystin-LR, okadaic acid, and the endogenous PP-1c, inhibitor protein inhibitor-2. A crystal structure of the chimeric mutant, in complex with okadaic acid was determined to 2.0-A resolution. The, beta12-beta13 loop region of the mutant superimposes closely with that of, wild-type PP-1c bound to okadaic acid. Systematic mutation of each residue, in the beta12-beta13 loop of PP-1c showed that a single amino acid change, (C273L) was the most influential in mediating sensitivity of PP-1c to, toxins. Taken together, these data indicate that it is an individual amino, acid residue substitution and not a change in the overall beta12-beta13, loop conformation of protein phosphatase-1 that contributes to disrupting, important interactions with inhibitors such as microcystin-LR and okadaic, acid.
About this Structure
1U32 is a Single protein structure of sequence from Homo sapiens with MN, OKA and BME as ligands. Active as Phosphoprotein phosphatase, with EC number 3.1.3.16 Full crystallographic information is available from OCA.
Reference
Crystal structure and mutagenesis of a protein phosphatase-1:calcineurin hybrid elucidate the role of the beta12-beta13 loop in inhibitor binding., Maynes JT, Perreault KR, Cherney MM, Luu HA, James MN, Holmes CF, J Biol Chem. 2004 Oct 8;279(41):43198-206. Epub 2004 Jul 26. PMID:15280359
Page seeded by OCA on Mon Nov 12 19:30:47 2007
