1fa8
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(New page: 200px<br /><applet load="1fa8" size="450" color="white" frame="true" align="right" spinBox="true" caption="1fa8, resolution 1.7Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 12:38, 20 November 2007
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CRYSTAL STRUCTURE OF THE APO FORM GLYOXALASE I OF ESCHERICHIA COLI
Overview
The metalloenzyme glyoxalase I (GlxI) converts the nonenzymatically, produced hemimercaptal of cytotoxic methylglyoxal and glutathione to, nontoxic S-D-lactoylglutathione. Human GlxI, for which the structure is, known, is active in the presence of Zn(2+). Unexpectedly, the Escherichia, coli enzyme is inactive in the presence of Zn(2+) and is maximally active, with Ni(2+). To understand this difference in metal activation and also to, obtain a representative of the bacterial enzymes, the structure of E. coli, Ni(2+)-GlxI has been determined. Structures have also been determined for, the apo enzyme as well as complexes with Co(2+), Cd(2+), and Zn(2+). It is, found that each of the protein-metal complexes that is catalytically, active has octahedral geometry. This includes the complexes of the E. coli, enzyme with Ni(2+), Co(2+), and Cd(2+), as well as the structures reported, for the human Zn(2+) enzyme. Conversely, the complex of the E. coli enzyme, with Zn(2+) has trigonal bipyramidal coordination and is inactive. This, mode of coordination includes four protein ligands plus a single water, molecule. In contrast, the coordination in the active forms of the enzyme, includes two water molecules bound to the metal ion, suggesting that this, may be a key feature of the catalytic mechanism. A comparison of the human, and E. coli enzymes suggests that there are differences between the active, sites that might be exploited for therapeutic use.
About this Structure
1FA8 is a Single protein structure of sequence from Escherichia coli. Active as Lactoylglutathione lyase, with EC number 4.4.1.5 Full crystallographic information is available from OCA.
Reference
Determination of the structure of Escherichia coli glyoxalase I suggests a structural basis for differential metal activation., He MM, Clugston SL, Honek JF, Matthews BW, Biochemistry. 2000 Aug 1;39(30):8719-27. PMID:10913283
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