1mnq

Thioesterase Domain of Picromycin Polyketide Synthase (PICS TE), pH 8.4

spinqualitylabelsall models 1mnq, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1mnq is a 2 chain structure with sequence from Streptomyces venezuelae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1kez, 1mn6, 1mna, 1mo0 Gene: picAIV (Streptomyces venezuelae) Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Modular polyketide synthases (PKSs) synthesize the polyketide cores of pharmacologically important natural products such as erythromycin and picromycin. Understanding PKSs at high resolution could present new opportunities for chemoenzymatic synthesis of complex molecules. The crystal structures of macrocycle-forming thioesterase (TE) domains from the picromycin synthase (PICS) and 6-deoxyerythronolide B synthase (DEBS) were determined to 1.8-3.0 A with an R(crys) of 19.2-24.4%, including three structures of PICS TE (crystallized at pH 7.6, 8.0, and 8.4) and a second crystal form of DEBS TE. As predicted by the previous work on DEBS TE [Tsai, S. C., et al. (2001) Proc. Natl. Acad. Sci. U.S.A. 98, 14808-14813], PICS TE contains an open substrate channel and a hydrophobic dimer interface. Notwithstanding their similarity, the dimer interfaces and substrate channels of DEBS TE and PICS TE reveal key differences. The structural basis for the divergent substrate specificities of DEBS TE and PICS TE is analyzed. The size of the substrate channel increases with increasing pH, presumably due to electrostatic repulsion in the channel at elevated pH. Together, these structures support previous predictions that macrocycle-forming thioesterases from PKSs share the same protein fold, an open substrate channel, a similar catalytic mechanism, and a hydrophobic dimer interface. They also provide a basis for the design of enzymes capable of catalyzing regioselective macrocyclization of natural or synthetic substrates. A series of high-resolution snapshots of a protein channel at different pHs is presented alongside analysis of channel residues, which could help in the redesign of the protein channel architecture. Insights into channel architecture and substrate specificity from crystal structures of two macrocycle-forming thioesterases of modular polyketide synthases.,Tsai SC, Lu H, Cane DE, Khosla C, Stroud RM Biochemistry. 2002 Oct 22;41(42):12598-606. PMID:12379102 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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