3oac | pdb_00003oac

Mint deletion mutant of heterotetrameric geranyl pyrophosphate synthase in complex with ligands

spinqualitylabelsall models 3oac, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3oac is a 4 chain structure with sequence from Menpi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: DST, IPE, MG Related: 3kra, 3krc, 3krf, 3kro, 3krp, 3oab Activity: Dimethylallyltranstransferase, with EC number 2.5.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Isoprenoids, most of them synthesized by prenyltransferases (PTSs), are a class of important biologically active compounds with diverse functions. The mint geranyl pyrophosphate synthase (GPPS) is a heterotetramer composed of two LSU.SSU (large/small subunit) dimers. In addition to C(10)-GPP, the enzyme also produces geranylgeranyl pyrophosphate (C(20)-GGPP) in vitro, probably because of the conserved active-site structures between the LSU of mint GPPS and the homodimeric GGPP synthase from mustard. By contrast, the SSU lacks the conserved aspartate-rich motifs for catalysis. A major active-site cavity loop in the LSU and other trans-type PTSs is replaced by the regulatory R-loop in the SSU. Only C(10)-GPP, but not C(20)-GGPP, was produced when intersubunit interactions of the R-loop were disrupted by either deletion or multiple point mutations. The structure of the deletion mutant, determined in two different crystal forms, shows an intact (LSU.SSU)(2) heterotetramer, as previously observed in the wild-type enzyme. The active site of LSU remains largely unaltered, except being slightly more open to the bulk solvent. The R-loop of SSU acts by regulating the product release from LSU, just as does its equivalent loop in a homodimeric PTS, which prevents the early reaction intermediates from escaping the active site of the other subunit. In this way, the product-retaining function of R-loop provides a more stringent control for chain-length determination, complementary to the well-established molecular ruler mechanism. We conclude that the R-loop may be used not only to conserve the GPPS activity but also to produce portions of C(20)-GGPP in mint. Enhanced Specificity of Mint Geranyl Pyrophosphate Synthase by Modifying the R-Loop Interactions.,Hsieh FL, Chang TH, Ko TP, Wang AH J Mol Biol. 2010 Oct 19. PMID:20965200 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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