1qml
Hg complex of yeast 5-aminolaevulinic acid dehydrataseHg complex of yeast 5-aminolaevulinic acid dehydratase
Structural highlights
FunctionHEM2_YEAST Catalyzes an early step in the biosynthesis of tetrapyrroles. Binds two molecules of 5-aminolevulinate per subunit, each at a distinct site, and catalyzes their condensation to form porphobilinogen. 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 PubMedMAD experiments attempting to solve the structure of 5--aminolaevulinic acid dehydratase using Zn and Pb edges are described. The data obtained proved insufficient for a complete structure solution but were invaluable in subsequent identification of metal-binding sites using anomalous difference Fourier analyses once the structure of the enzyme had been solved. These sites include the highly inhibitory substitution of an enzymic cofactor Zn(2+) ion by Pb(2+) ions, which represents a major contribution towards understanding the molecular basis of lead poisoning. The MAD data collected at the Pb edge were also used with isomorphous replacement data from the same Pb co-crystal and a Hg co-crystal to provide the first delineation of the enzyme's quaternary structure. In this MADIR analysis, the Hg co-crystal data were treated as native data. Anomalous difference Fouriers were again used, revealing that Hg(2+) had substituted for the same Zn(2+) cofactor ion as had Pb(2+), a finding of fundamental importance for the understanding of mercury poisoning. In addition, Pt(2+) ions were found to bind at the same place in the structure. The refined structures of the Pb- and the Hg-complexed enzymes are presented at 2.5 and 3.0 A resolution, respectively. MAD analyses of yeast 5-aminolaevulinate dehydratase: their use in structure determination and in defining the metal-binding sites.,Erskine PT, Duke EM, Tickle IJ, Senior NM, Warren MJ, Cooper JB Acta Crystallogr D Biol Crystallogr. 2000 Apr;56(Pt 4):421-30. PMID:10739915[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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