2c3z | pdb_00002c3z

Crystal structure of a truncated variant of indole-3-glycerol phosphate synthase from Sulfolobus solfataricus

spinqualitylabelsall models 2c3z, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2c3z is a 1 chain structure with sequence from Saccharolobus solfataricus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.8Å Ligands: SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TRPC_SACS2 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 Indole-3-glycerol phosphate synthase (IGPS) catalyzes the fifth step in the biosynthesis of tryptophan. It belongs to the large and versatile family of (betaalpha)(8)-barrel enzymes but has an unusual N-terminal extension of about 40 residues. Limited proteolysis with trypsin of IGPS from both Sulfolobus solfataricus (sIGPS) and Thermotoga maritima (tIGPS) removes about 25 N-terminal residues and one of the two extra helices contained therein. To assess the role of the extension, the N-terminally truncated variants sIGPSDelta(1-26) and tIGPSDelta(1-25) were produced recombinantly in Escherichia coli, purified, and characterized in comparison to the wild-type enzymes. Both sIGPSDelta(1-26) and tIGPSDelta(1-25) have unchanged oligomerization states and turnover numbers. In contrast, their Michaelis constants for the substrate 1-(o-carboxyphenylamino)-1-deoxyribulose 5-phosphate are increased, and their resistance toward unfolding induced by heat and guanidinium chloride is decreased. sIGPSDelta(1-26) was crystallized, and its X-ray structure was solved at 2.8 A resolution. The comparison with the known structure of sIGPS reveals small differences that account for its reduced substrate affinity and protein stability. The structure of the core of sIGPSDelta(1-26) is, however, unchanged compared to sIGPS, explaining its retained catalytic activity and consistent with the idea that it evolved from the same ancestor as the phosphoribosyl anthranilate isomerase and the alpha-subunit of tryptophan synthase. These (betaalpha)(8)-barrel enzymes catalyze the reactions preceding and following IGPS in tryptophan biosynthesis but lack an N-terminal extension. Role of the N-terminal extension of the (betaalpha)8-barrel enzyme indole-3-glycerol phosphate synthase for its fold, stability, and catalytic activity.,Schneider B, Knochel T, Darimont B, Hennig M, Dietrich S, Babinger K, Kirschner K, Sterner R Biochemistry. 2005 Dec 20;44(50):16405-12. PMID:16342933 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also IGPS 3D structures

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