1b4k

High resolution crystal structure of a MG2-dependent 5-aminolevulinic acid dehydrataseHigh resolution crystal structure of a MG2-dependent 5-aminolevulinic acid dehydratase

Structural highlights 1b4k is a 2 chain structure with sequence from Pseae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: , , Gene: HEMB (PSEAE) Activity: Porphobilinogen synthase, with EC number 4.2.1.24 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 Common to the biosynthesis of all known tetrapyrroles is the condensation of two molecules of 5-aminolevulinic acid to the pyrrole porphobilinogen catalyzed by the enzyme porphobilinogen synthase (PBGS). Two major classes of PBGS are known. Zn2+-dependent PBGSs are found in mammals, yeast and some bacteria including Escherichia coli, while Mg2+-dependent PBGSs are present mainly in plants and other bacteria. The crystal structure of the Mg2+-dependent PBGS from the human pathogen Pseudomonas aeruginosa in complex with the competitive inhibitor levulinic acid (LA) solved at 1.67 A resolution shows a homooctameric enzyme that consists of four asymmetric dimers. The monomers in each dimer differ from each other by having a "closed" and an "open" active site pocket. In the closed subunit, the active site is completely shielded from solvent by a well-defined lid that is partially disordered in the open subunit. A single molecule of LA binds to a mainly hydrophobic pocket in each monomer where it is covalently attached via a Schiff base to an active site lysine residue. Whereas no metal ions are found in the active site of both monomers, a single well-defined and highly hydrated Mg2+is present only in the closed form about 14 A away from the Schiff base forming nitrogen atom of the active site lysine. We conclude that the observed differences in the active sites of both monomers might be induced by Mg2+-binding to this remote site and propose a structure-based mechanism for this allosteric Mg2+in rate enhancement. High resolution crystal structure of a Mg2+-dependent porphobilinogen synthase.,Frankenberg N, Erskine PT, Cooper JB, Shoolingin-Jordan PM, Jahn D, Heinz DW J Mol Biol. 1999 Jun 11;289(3):591-602. PMID:10356331 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Porphobilinogen synthase

spinqualitylabelsall models 1b4k, resolution 1.67Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image