1fj2
From Proteopedia
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Crystal structure of the human acyl protein thioesterase 1 at 1.5 A resolution
Contents |
Overview
BACKGROUND: Many proteins undergo posttranslational modifications, involving covalent attachment of lipid groups. Among them is, palmitoylation, a dynamic, reversible process that affects trimeric G, proteins and Ras and constitutes a regulatory mechanism for signal, transduction pathways. Recently, an acylhydrolase previously identified as, lysophospholipase has been shown to function as an acyl protein, thioesterase, which catalyzes depalmitoylation of Galpha proteins as well, as Ras. Its amino acid sequence suggested that the protein is, evolutionarily related to neutral lipases and other thioesterases, but, direct structural information was not available. RESULTS: We have solved, the crystal structure of the human putative Galpha-regulatory protein acyl, thioesterase (hAPT1) with a single data set collected from a crystal, containing the wild-type protein. The phases were calculated to 1.8 A, resolution based on anomalous scattering from Br(-) ions introduced in the, cryoprotectant solution in which the crystal was soaked for 20 s. The, model was refined against data extending to a resolution of 1.5 A to an R, factor of 18.6%. The enzyme is a member of the ubiquitous alpha/beta, hydrolase family, which includes other acylhydrolases such as the, palmitoyl protein thioesterase (PPT1). CONCLUSIONS: The human APT1 is, closely related to a previously described carboxylesterase from, Pseudomonas fluorescens. The active site contains a catalytic triad of, Ser-114, His-203, and Asp-169. Like carboxylesterase, hAPT1 appears to be, dimeric, although the mutual disposition of molecules in the two dimers, differs. Unlike carboxylesterase, the substrate binding pocket and the, active site of hAPT1 are occluded by the dimer interface, suggesting that, the enzyme must dissociate upon interaction with substrate.
Disease
Known diseases associated with this structure: Autoimmune lymphoproliferative syndrome OMIM:[134637], Autoimmune lymphoproliferative syndrome, type IA OMIM:[134637], Squamous cell carcinoma, burn scar-related, somatic OMIM:[134637]
About this Structure
1FJ2 is a Single protein structure of sequence from Homo sapiens with as ligand. Active as Alkylglycerophosphoethanolamine phosphodiesterase, with EC number 3.1.4.39 Known structural/functional Sites: and . Full crystallographic information is available from OCA.
Reference
Crystal structure of the human acyl protein thioesterase I from a single X-ray data set to 1.5 A., Devedjiev Y, Dauter Z, Kuznetsov SR, Jones TL, Derewenda ZS, Structure. 2000 Nov 15;8(11):1137-46. PMID:11080636
Page seeded by OCA on Sun Feb 3 09:39:54 2008
