4c1k

Crystal structure of pyrococcus furiosus 3-deoxy-D-arabino- heptulosonate 7-phosphate synthase

spinqualitylabelsall models 4c1k, resolution 2.15Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4c1k is a 6 chain structure with sequence from Pyrococcus furiosus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.15Å Ligands: 2PE, CD, CL, CO3, PEP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8U0A9_PYRFU Publication Abstract from PubMed Many proteins adopt homomeric quaternary structures to support their biological function, including the first enzyme of the shikimate pathway that is ultimately responsible for the biosynthesis of the aromatic amino acids in plants and microorganisms. This enzyme, 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase (DAH7PS), adopts a variety of different quaternary structures depending on the organism in which it is found. The DAH7PS from the hyperthermophilic archaebacterium Pyrococcus furiosus was previously shown to be tetrameric in its crystalline form, and this quaternary association is confirmed in an improved structure in a different crystal system. This tetramer is also present in solution as revealed by small-angle X-ray scattering and analytical ultracentrifugation. This homotetrameric form has two distinct interfaces, both of which bury over 10% each of the surface area of a single monomer. Substitution of Ile for Asp in the hydrophobic region of one interface gives a protein with a remarkable 4-fold higher maximum catalytic rate than the wild-type enzyme. Analytical ultracentrifugation at pH7.5 reveals that the tetrameric form is destabilized; although the protein crystallizes as a tetramer, equilibrium exists between tetrameric and dimeric forms with a dissociation constant of 22muM. Thus, under the conditions of kinetic assay, the enzyme is primarily dimeric, revealing that the dimeric form is a fully functional catalyst. However, in comparison to the wild-type protein, the thermal stability of the dimeric protein is significantly compromised. Thus, an unusual compromise of enzymatic activity versus stability is observed for this DAH7PS from an organism that favors a hyperthermophilic environment. Destabilization of the Homotetrameric Assembly of 3-Deoxy-d-Arabino-Heptulosonate-7-Phosphate Synthase from the Hyperthermophile Pyrococcus furiosus Enhances Enzymatic Activity.,Nazmi AR, Schofield LR, Dobson RC, Jameson GB, Parker EJ J Mol Biol. 2013 Nov 14. pii: S0022-2836(13)00719-5. doi:, 10.1016/j.jmb.2013.11.008. PMID:24239948 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DAHP synthase 3D structures

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