1qml

From Proteopedia

Revision as of 14:57, 5 November 2007

HG COMPLEX OF YEAST 5-AMINOLAEVULINIC ACID DEHYDRATASE

Overview

MAD 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.

About this Structure

1QML is a Single protein structure of sequence from Saccharomyces cerevisiae with HG as ligand. Active as Porphobilinogen synthase, with EC number 4.2.1.24 Structure known Active Site: CAT. Full crystallographic information is available from OCA.

Reference

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

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